Alright, even though I have no big expectations for this to get through to the stubborn head of any Bluehole employee under any circumstance, here goes.
Warning: Huge wall of text, nearly 3000 words.
Now, before I begin, some things of what I am about to say may sound new-player-unfriendly or elitist, but In my honest opinion, the game has become way too forgiving for this part of the playerbase during the earlier dungeons until they hit a difficulty spike in the later ones, causing them to be nuisances to any party they run with. The game lacks general tutorials and in my honest opinion, the average player skill level is at an all-time low - people wipe even in dungeons that you could consider braindead easy. I think it's a burden and, in some cases, outright insulting to seasonal players to have to deal with players that aren't up to that standard. It is honestly in my best interest that this situation betters itself, and players are able to run content without any worries - and getting newer and below-average players up to the standard with actually effective techniques, and not new gear that Krafton/Bluehole believe is the right way to equalize player skill differences, is one of the things that I think needs serious consideration.
General changes:
Instance Matchmaking: Skill based Matchmaking or further filtering options
This is where what I just mentioned first starts off - I think the instance matchmaker needs an overhaul to be able to function more as a tool to find actual parties with to clear content, or find more like-minded people to play and/or learn content with. In other words, make matchmaking skill-based, so rookies only get matched with rookies, wheras other players get matched according to their total runs.
You could of course expand on this further: Make rookies unable to queue for anything but learning runs until they have the "skilled" status - this will force them to either deal with that, and actually take the time to learn the dungeon, or, in case of an alt, run the dungeon via LFG. If you want to loosen this restriction up, you could ease up the requirement to having the dungeon skilled according to total runs over all your characters, but consequently raise the amount of runs needed to attain "skilled".
You could also add the option to state preferences: which Healer do you want, what Tank do you prefer? Are you willing to join learning runs (and if a skilled player does so, offer them increased rewards - right now the current Rookie-Assist rewards are forgettable save for the coins), do you want to just have a fun time, or do you want to have some fast/efficient speedruns? You could improve the IMS with added variety like this.
Of course, Korea doesn't even have that issue because their response was to just merge their servers into one, thus they LFG or play with statics/guild mates far more often - despite their ever shrinking playerbase.
If you really want to take it to the extreme, you could lock out people of certain harder dungeons until they have a certain amount of runs in the preceeding ones - as a safety check that the players actually have enough game sense to even tackle them.
Of course, there was a lot of power creep introduced, making dungeons even easier for veterans, but newer players, while direly needed, are left behind in the dust and quit, or become nuisances to other parties while being unskilled.
This brings me to my second point:
Add Training rooms / Learning Versions for a variety of dungeons.
These can be solo versions of a dungeon where you can safely practice the mechanics of a dungeon, as well as improve upon your playstyle in a fight with actual mechanics, and not just a sandbag like the Crab in the current dungeon. You can achieve that by making all enemies deal no damage, but inflicting a stun debuff or anything similar in the case a player messes up. Blade & Soul has a similar Training room like this.
Add Level 70 / Very Hard/Legacy Versions of previously nerfed/removed dungeons, or buff/rebalance them.
This is to counteract the power-creep that got introduced with the level 70-patch, which made many of the former 4-and 5 star dungeons very easy for any seasoned player.
The goal of this would be to bring those dungeons back to the difficulty they had at the time they were released in, basically non-powercreeped versions, so to speak. You could spice this up even more by adding a few new mechanics in - as those will be existing/reused dungeons after all, adding a bit of direly needed variety of content and fresh air - that being said, make sure to make those dungeons actually rewarding as well, equivalent to dungeons of the same difficulty. For example, if you took RK9-Lv 70/Very Hard mode, the dungeon is supposed to be as difficult as RKEM during its release, with according rewards befitting the current content - for example Gold gear, with a higher chance than in AQ, Feedstocks, Relics/Halidoms, Pets, New Innerwear, Etching Materials, Weapon Skins and perhaps even the (now) proposed upgrade scrolls that K-TERA will get in their newest dungeon.*
Variety, as I said, is a big factor, and many people would actually love to see dungeons like Manayas Core, Abscess, hell, even Wonderholme and Rifts Edge - as unfun as some of those dungeons were - back. Having an alternative dungeon to run for materials in case you didn't like the existing option was a huge selling point of the Extreme mode event dungeons that we had gotten.
* http://tera.nexon.com/news/gmnote/View.aspx?n4ArticleSN=439 - Sadly, this dungeon will - according to what people leaked so far - consist of reskinned bosses and is also very entry-limited and gated by an item drop - absolute garbage!
Unrelated, but this needs to be mentioned: Remove downgrading from gear over +10, the chances are already abysmally low, and downgrading already was badly received the first time it existed during VM4, where added with the MWA crisis it made a lot of players quit/cancel their TC subscription until something was changed. We are currently in a similar situation with the current gear, except even worse where the rewards in relation to the coin cost are absurdly terrible, and feedstock is extremely scarce and a pain to farm.
With coins being mentioned, and my point of adding more variety to the game, here is, on a related note, another suggestion:
Scrap the Entry-Coin system entirely for the old one, or increase its cap and/or methods to actually get coins.
The big disadvantage of the current coin system is that once you run ONE particular dungeon a certain amount of times, you won't be able to run ANY other dungeon on the same character. This takes away a lot of flexibility and is a problem that didn't exist in the past. Back then, the issue with dungeons runs was that you were gated by the cooldown of your reset scrolls. Simply removing it would have, in my opinion, led to a much better outcome than the coin system.
Alternatively, you could of course also make coins more readily available, for example, by putting 200 coin-packages into the Vanguard Merchant.
Cooldown resets before every Boss in every Dungeon.
You know when you run with Valkyries and have to wait 3-4 minutes for their Godsfall to come up, or certain mystics that don't want to go without their Thrall lord, making you waste even more time? Why not add a crystal or some mechanic that resets all cooldowns in front of every boss so you can cut those waiting times down?
Furthermore, you could implement that the remaining usage timer of Consumables gets PAUSED when not inside combat - KTERA tested this and it worked out, and I wonder why this was never fully implemented in the first place. This is huge QOL change.
NO LARGE RAID DUNGEONS:
The current mindset and playerbase in this community cannot properly support raid dungeons due to lack of players (particularly those of similar skill-level) as well as the good old fashioned drama that exists within this community. Kelsaiks Nest was already quite difficult to raid up for, anything beyond that seems like a near-impossiblity at this point.
This doesn't even tackle the issues with the game optimization which cannot properly support Raids either.
Revamp Elleon's Token shop:
Save for the consumables, items in the Elleon's Token shop have become obsolete, with the Enchanter Supply coffers being no longer really needed for any player that plays endgame-content, except for jewelry.
As a suggestion, you should add a way to obtain the new Dark Shard Weapon-and Armor Feedstocks in the Token store. This would also limit the absurd open world grinding required to make any progress with the new gear right now. You could also add the weaker/rare versions of the new consumables - at a slightly higher price, given they are actually stronger than the current ones.
Don't just outright remove the enchanters coffers though, as this would kill any reliable source of silver darics which are still needed for jewelry.
Those are just some of the overall changes I would suggest. Now for specific dungeons:
Akalath Quarantine:
Kashir: The randomly occuring KD into double slash mechanic is extremely frustrating for non-brawler-tanks, and often lethal outside of enrages, since you have almost no window to properly react to it. Either give it a proper warning or remove it entirely.
Loot:
Extremely unrewarding. Either increase the drop chance of gear in general, or add Tokens to either the Vanguard or the loot-table which allow you to FREELY CHOOSE the item you wish to obtain. This would also serve to counteract part of the absurd RNG that is presented with the new gear.
Bahaar:
Add a legacy mode, balanced for the new gear, with a few new attacks and mechanics.
Fix the stun-mechanic bug that can, in the worst case, cause wipes.
Fix D-Stance Warrior's Rain of Blows option on PH2 Bahaar.
Fix the Laser delay.
GVHM:
Nerf the HP drain mechanic to be independent of people alive/dead.
Release a legacy/very hard mode for the original iteration without aforementioned change with slightly buffed HP.
AAHM, RKEM, RMHM, SSHM, FIHM, TSHM, SCHM, ABHM, WHHM, MCHM, ACHM, FOKHM, BTHM:
Add legacy/very hard modes to some* of those dungeons that were endgame content during their respective period, and reward them accordingly since they should be balanced for the new gear (as in, balanced to be harder than AQ without going overboard). Add a few new attacks or mechanics to spice things up.
Another idea is to simply buff the dungeons to counteract the powercreep that all the recent patches have introduced to them.
*Variety is good, but too much variety can cause chaos and will lead to LFGs never filling up.
RG, TRNM, CW, LKNM:
Rebalance these dungeons and their loot table for - at least - Item Level 439, as their materials are completely useless, and there is no purpose in running them other than for the associated quests.
Ghillieglade:
Update the loot, Ghillieglade still drops materials for Guardian gear which is no longer obtainable.
Add new armor/weapon feedstocks to it instead.
Multiple old dungeons and AANM/AAHM first boss:
Remove random staggers/KDs. None of the newer bosses have unpredictable or random CCs, and still having them on old bosses (which includes Ghergof, as it is literally a reskinned Melkatran from MCHM with altered mechanics) not only is inconsistent, but doesn't add well to how the combat in this game has developed.
Bring back a revamped Crucible of Flame!
COF was a funny, competitive dungeon back in the day, and would certainly not be unwelcomed as added variety. To spice things up, you could add weapon skins, mounts (Smolder) and accessories (Ghost Knight Helm) here as an extra incentive to run it.
Dreadspire:
Out of all iterations of Dreadspire, should the Legacy-Dungeon idea be impossible, I would suggest adding the first iteration of DSEM - the one with 22 Floors, and no hard wipes, but challenging bosses, as a permanent dungeon. While it took long to clear, it was also very rewarding and fun to run.
You could experiment with the mechanic from the second iteration of DSEM, that allowed for a variety of bosses to be spawned, as well. However, it is imperative that the different bosses are actually balanced with one another this time, should this ever be done again.
For future Dungeons:
Less reskinning, more original bosses. Dungeons become stale very very quickly if half the attack patterns are already familiar from other bosses.
More, balanced mechanics that don't favor a certain class or just screw over one member of the party.
Fair challenges, no artificial and fake difficulty via HP/Tankiness walls.
Finally, to round up this post, I want to give Feedback to the latest event dungeons that we had time to run in the last few patches. As such, this is also adressed to GameForge, as they are partially responsible for the design of the Event Dungeons.
FIEM/FIRD:
This was honestly fine as it was.
BREM:
While the first boss was fine, the second one was a nightmare for any melee class.
Some of the spin attacks had literally no warning, often causing lethal amounts of damage out of seemingly nowhere. This doesn't even touch the problem with the constant staggers that Tantibus throws out. If you were to iframe all of those, most Melee classes couldn't even do it, as the boss spammed this attack so much that you would just run out of iframes. Thus, remove this stagger entirely (see above).
On an added note, make the drain mechanic iframable, or remove the fear that follows afterward from it, as due to this, the constant repositioning and other issues you are sometimes unable to avoid this attack despite all efforts.
Also, the mechanic that requires you to KD the boss is pure RNG, and very frustrating if the boss resists every attempt of kding. Either make sure there is a safe way to do this mechanic, or remove the fear that follows after it.
As for the last boss, it has too many phases in which it is undamageable, making the fight extremely long. Thus, the solution is simple, cut down on those phases or nerf the bosses' HP. Other than that, there are no issues.
SCEM:
Shorten the mob phase, after some runs it becomes extremely boring.
Darkan: Remove the fireball mechanic, as for many people, the balls were invisible and thus they couldn't even properly avoid them. Furthermore, eliminate the chance of random single backswipes happening, as they can just silence the entire party for no reason, and lead to chaos.
KNEM:
Fine as is, but suffers from the same issues as all other raids, as stated above.
REEM:
I'll be completely honest, this dungeon is a total failure and unless it is completely revised, it should never be released in this state again. It took way too long for what it is worth, and is probably one of the most unfun dungeons ever released.
All of the minibosses have too much HP and/or are extremely unfun to deal with, either because they KD/Stagger you to infinity (see above) or decide to reset themselves.
Yativios inner oneshot AOE has no reliable way to be recognized in advance under 30%, as the boss uses the same animation for this attack for a multitude of attacks and actions. It also KDs and staggers absurdly often. The suicide-bombing potatoes sometimes take ages to finally explode, which is especially frustrating if they target the tank, as they can get KD-chained by the boss just before they explode while trying to evade them. Finally, due to the amount of mobs it spawns, it can also become extremely laggy.
Vesporax, similar to Fulminar, also has too many phases in which it can't be attacked due to the puddles, and there is no way to tell when the ground is safe again, this is especially annoying once it gains the attack speed stacks, as it will finish its attack animation much sooner, which can lead to players mistakingly charging into the boss and dying. This boss too KDs / staggers too randomly/often on some attacks.
Koleogg is the only boss that can be considered fine in this dungeon.
DSEM:
Neither Floor 1 or 2 were properly balanced for their recommended gear - all of the bosses dealt way too much damage, the most absurd being Akasha.
Hrathgol: Nightmarish for many melee classes, in my opinion, it does the bleeding debuff mechanic too often.
Argon Predator: Puddles on the tank should not happen, especially when tanking space is already very limited during this fight.
Thulsa: Was okayish except for one thing: the ball mechanic was sometimes inconsistent, and furthermore, it could lag out or even crash people with lower end PCs.
Akasha: Actually nerf the bosses' damage this time. When it was announced that the bosses' damage dealt would be nerfed, the end result was that it got actually buffed. Akasha dealt way too much damage to any tank regardless of the gear, and coupling that with the mechanic that added a debuff to healers that turned heals into damage for as long as it was active, this was extremely brutal - and extremely frustrating for tanks and melee DPS especially.
Kaprima: Was mostly fine.
Meldita: Was also fine.
Manaya: What a boss should be. I would fix the hitbox issues though, and buff the bosses' overall sustainability.
Saravash: Increase the visiblity of the oneshot-ball and make it impossible for it to spawn directly in somebody's face. Reportedly, players also faced issues with the ball not rendering properly. This should be fixed.
Furthermore, Saravash's backtail attack has not much of a warning and deals absurd amounts of damage, this should probably be toned down a bit.
And that's it, that's all of the feedback I can share for the current and/or removed dungeons that I currently have to share. It is very likely I forgot many ideas here and there, and if that is the case I will most likely return to write those down as well.
Feel free to add onto those suggestions, for example, if you have a suggestion for a new mechanic for those legacy dungeons, share it here. If you have anything to add to the general suggestions, let me know.
Cheers, Assa
P.S.: As a final suggestion, adressed towards Bluehole: Please fire Jerry, thanks.