Single Class Wizard Evoker, at lvl 8-ish once you get access to tier 4 spell, there this spell call Lloetta*** concussive missle can destroy 3 enemy in 1 cast, the higher level you are the more OP that spell is, only the dragon and final boss can survive 1 hit of this spell. My first playthrough potd pose no challenge whatsoever, boring story, no combat challenge.
If u wanna go Melee Wizard, go Enchanting Wizard + any fighting class (ranger,rogue,fighter,bar,monk), the best buff won't come until very very late