It is quite complicated to specify, but in term of single target burst all I can say that many standalone classes are sufficient to kill a 2m HP boss under 10s with decent gears/cards/attributes.
eg: Enchanter2/Elem3/Warlock3/Shadow2/Featherfoot3, with Elementalist3 have the best AoE ability.
But out of this ability, what else are you seeking? What game content you like the most?
ET
The next ET will be changed, many classes can deal AoE, especially new Clericsss/Mergen/Cannoneer/BulletMarker. Elememe as now is not compulsory anymore as it too tied with cryo3chrono3, the best classes for ET could be Cryo3-Chrono3-Enchanter2 now, since its party support is irreplaceable compare to elememe’s dps role. Even if you still want to be in ET, you can go Elem3Warlock3 or Elem3Chrono3, Invocation is still OP for Mobs cleaning, and Mastema is still strong and good support for Cleric/BulletMarker holy damage debuff.
PvP/GvG/TBL
I think Thauma3Shadow2 or Cryo3Chrono3Shadow2 or Cryo3Psycho3Shadow2 would be best, as mentioned by rayden you can go full con and transpose full int to get buff, then cancel tranpose to remain as high matk + tanky build. All recent changes has made this possible, remove buff count / random gear stats / new cards system.
HG350/DG330 Farming
I think Cryo3Thaum3Enchanter2/Cryo3Chrono3Enchanter2 would be best, as they are able to deal sustainable damage with utility, chrono3 for speed clear or thaum3 for swell body x2 drop. The simplicity of the build fit with the mindless farming.
Cryo3 is essentially the best mobs grouping skill in the game
World Bosses rank1 race
I don’t know, but it seems we will lose to other classes like Murmillo or Zealot or Musketeer in term of solo dps, but if you have support party that central around you would be different. Mostly we are quite disadvantageous with Shadow/Warlock being dark element or most skills need to wait CD. Then, Elem3Warlock1Shadow2 or Elem3FF3 can give it a try
Finally, there are more niche hybrid builds that are good or even better in between, or need a lot of resources (not beginner friendly) to become good, *multiple characters, fix party member, silvers, skill scrolls, specific cards (gazing golem) and summoner’s card (marnox).
p/s: Sage i’m not forgetting you but i can’t find anything to mention about you.