Mithos is also the guy who teleports out of any combo that doesn't instantly stun him, granted. And he can actually take a hit and keep on doing whatever it is he was doing, it's part of what makes him not fail completely. The giant mech form staggers more often for some stupid reason >_>
In ToS, all of your mages can get Compound EX skills that prevent them from getting knocked out of casting their spells. Of course, you tend not to use it for Colette since controlling her is more a case of spamming her techs like Para Ball and Ray Satellite, but if you do the arena with Raine and Genis you will almost certainly need to use it in order to win. Unless you've got some crazy strategy involving physicals and only using wimpy level 1 spells, and even then a lot of enemies there will run up on you while you're casting.
I think you could safely assume that they'd always use this in a 1-on-1 environment, so you could give it to them without the effects of the EX Skills that add up to it. Generally, even high level magic will get fired off after a full combo is done hitting them, so they're still looking a little slow, but not enough to totally cripple them. Now granted, any spell cast-time stuff I'm remembering might have been skewed by EX Skills and Mystic Symbols, but I'm pretty certain that even Indignation won't be giving the opponent time for two whole combos. Enemy AI tends to never ever actually dodge even the most blatantly obvious spells, though I'd certainly put stuff like Indignation as being easily evadable by those who have decent ability for evading magic, and probably missing anyone else not the size of Evil Gaia on occasion. Most people who don't die in three shots of it are bosses, magic tanks that are built for fighting mages like Genis, or Lightning-resistant, in which case he just uses Meteor Storm (unevadable!) at the cost of more speed, or his third best damage which was Explosion if he's T side for Indignation, Prism Sword on S Side.
