My party (20 level now) contain Pyro-hydromancer (hydro is mostly for healing and frost skills in case of enemies with resists) Aero-hydromancer (more heals is always better, i don't even use potions, and lightnings for stuns and more flexibility with resist) - both with Glass Cannons. And pyro have spider for enemies with all-magic rez.
Second main is tank-warrior, almost 2k HP, insane damage on Rage and mass debuffs, aoe attacks and stuns (real monstes, almost immortal)
Last is melee rogue, i don't know why i still didn't swap him. Damage is bugged (1h dagger without shield should strike twice, it was for some time but then bugged again and i have only one hit.), dodge is nice, but for decent damage always must stay behind enemy. And walking on burning ground does damage on every step (it is always burning and everywhere, cause pyramoncer is hardcore)