It just seems completely out of place and way overpowered. They're almost impossible to dodge, blocking seems useless and they seem to ignore my armor. Almost every other enemy I fight feels like they're at a comfortable difficulty, but these guys show up in the middle of them sometimes and I just get destroyed in seconds and it doesn't feel like there's anything I can do about it.
The NPC mages do around 10x the damage as what the player can with the same spells. They also slow you down with ice in such a way that none of your spells ever do. I also like how the AI constantly skates left and right to avoid your own spells or arrows like Spider-Man, yet flawlessly can hit you with their own spells even when moving left and right and at sniper range away.
Most of the casters aren't too terribly difficult to avoid though. The biggest problem/imblance is the one-shot shock Mages that randomly appear even on Adept level. They literally kill you in 1-2 hits and Shock is NOWHERE near that strong.