The only mobs I find to be "over powered" would be any Mole family you fight for the rank 40 Leves. Had a Pt last night doing Rank 40 leves on 2 Stars over in Camp Broken Water; every time the Mole buried down and popped up it would one hit KO us mages at rank 37 ><, so it could just be it was cause we were 3 ranks lower (But I haven't had that kind of difficulty on any other leve doing it the same way) or it could just be cause Mages are super squishy versus moles ><.