Hello, and welcome to tera first of all
. I would suggest that you pick a class you feel most comfortable with, a class you like.. Picking the strongest meta to main wont be worth it in my opinion if you dont like the class.. I mean games are supposed to be fun arent they?
Now, to answer your question. Please bear in mind that every players individual skill plays a very important role on how strong your class will be, how "well" you use the meta to your advantage. Whatever class you pick, spend the time to learn it, otherwise no matter how strong it currently is, you will not perform well enough.
Metas change, but currently, fromwhat I have seen, and sites that show stats per dungeon,
when it comes to dps, top tier options are valkyrie (melee dps), warrior (melee but harder to master) and slaying berzerker.
As a tank myself, what I can tell you is this:
-Brawler: very good dps and very well survivability but non-existent party buffs.
-Lancer: low dps,very well survivability and very string and useful party buffs. These party buffs are what makes some top tier parties prefer a lancer on their party rather than a brawler. However both options are viable as tanks and it all comes down to what playstyle you prefer, aggressivw or supportive.
-Berzerker tank and warrior tank, dont even think about it if you ask me
As to healers i have absolutely no experience, but both are useful so it doesnt matter much
Best regards,
AL