Physh

My wizard is an unstoppable monster that invalidates most encounters (and I love it). Casters are only weak early on. Once you can cast two level four spells per encounter, they one-shot entire packs of mobs with a 'Pull of Eora' followed by an empowered 'Minoletta's Concussive Missiles'. Once you get to tier 7-9 spells, you can stealth up and one-shot entire encounters before combat begins. This is on veteran using the companion caster (who has very little might), but the overkill is so much that I'm pretty sure it would bleed over into PotD.