So let's point out what's not exactly right.
@PVP "Attack Speed/Cooldown Reduction (Debatable, both are good.)"
have fun pvping without aspeed on reaper (but he mentioned he not good in pvp so i'll let it slide)
"Whipsaw is a very interesting skill. It reaches out 11-12 meters and whilist active, with every hit you regenerate HP in PvE(Or stagger enemies in PvP)."
It's not "Or stagger" it's AND STAGGER and staggers very often in PvE too. Also he didn't mention by pendulum strike and double shear they are also PvP staggers.
"Shadow Reaping. This thing. 24/7 usage. Pop it whenever you can, cooldown reduction will make you burn through ♥♥♥♥. During Shadow Reaping, you can use this chain:
Death Spiral > Double Shear > Grim Strike > Sundering Strike"
First of all, you don't use it as soon as you can, you use it when it's most worth it (pop it at start of tshm fun and have fun doing half of burst while boss got damage reduce during donut) Also if you have mystic you should make sure you know when he will use contagion (either decide before fight or have him tell u when there's 30 sec cd on contagion) so you can have full burst during boss endurance decrease. And rotation he spoke of is subpar to pendulum-> whipsaw -> grim strike -> sundering, check any pro reaper and see what their rotation is, whoosh.
Smite is good positioning skill if you are next to boss you can use it to get behind him faster (just don't get stuck on boss hitbox or it's waste of dps)
I like to pop soul reversal sometimes when other stuff is on cd to get a bit more damage while using other skills (it ticks damage, almost nothing but better than archer poison I think and still some archers use poison for whatever reason >_>) I have glisteningly restorative dyad so I can't complain about mana, otherwise it's just waste of mana (also keep it for stun phases if boss got such)
Also small info about shadow lash - before you could make it never go on cd by either using death spiral or dodge after 1-2 hits, now it will just continue chain and go on cd after 4 hits even after those skills (though i find it to be an advantage since i can just dodge behind monster when he turns to me and continue shadow lash without slow starting animation again. (basically infinite shadow lash is no longer possible)
Retribution doesn't work vs projectiles (void pulse, arcane pulse, monster ranged attacks like mentioned kuma balls)
"Shadow Step is you basic iframe, which depends on your movement key. Once you press any movement key and cast the skill, you will jolt a meter or so in that direction."
More like 6-7 meters not "a meter"...
Shrouded Escape (...) you need to time it properly cause of its quick animation activation time.
Oh, so you mean exactly same as shadow step? whoosh~
Part about rotations:
"Death Spiral > Double Shear > Grim Strike(Repeat Grim if it resets its cooldown) > Sundering Strike" DO NOT, i repeat DO NOT USE GRIM STRIKE RIGHT AFTER IT RESETS, use death spiral first at least to give it additional 20% usually it's actually preferable to land sundering after grim reset, then do death spiral -> smite -> double shear -> grim strike (can remove smite i guess, helps managing cooldowns though)
Also small tip, if you going to use shadow reaping make sure you put shadow burst on cd first, then after reaping ends you have burst on low cd can do one of basic chains and then do shadow burst again without wasting it's cooldown.
I generally hate when people ask me "what are your rotations" because frankly i have none, i use skills based on situations and cooldowns, the best i could do was give importance to skills in which they should be always kept on cooldowns. Simply speaking you should keep amount of time that shadow burst and sundering strike are off cd to minimum.