Two Red Templar Shadows that shadow strike one after the other should put you back down to earth... well six feet under to be more precise. At least when you're below t3/t3&4 mats (nightmare, only real setting tbh, hard was too easy).
Also I find it strange not to find enemies cast dispel, am I just not seeing it happen or do they not have that spell?
My dwarf DW rogue on nightmare takes out foes unbelievably faster than an elven KE (hard setting also) that was my first playthrough.
If it weren't for the glitches I find sometimes with my dwarf, I'd rate melee rogues far more highly than Knight Enchanters.