Since Zemilia requested this fight, I feel the need to discuss every flaw I've found with this Ken in the past 20 minutes since that's about as long as I can stand having him on my roster.
-He can attack from the air while dashing. That's Darkstalkers territory, not MvC.
-His custom supers either make no sense (his stupid punch hyper) or they're just too easy to use (air Shippu Jinrai Kyaku).
-None of his attacks allow the automatic air recovering MvC3 Ken here helpfully demonstrated that should be common knowledge among MvC coders.
-CvS voices? They clash a lot with the spriting.
-Why is his gi in the default palette the same as Reu's Evil Ken? It makes no sense and just doesn't fit for Ken's cheery self.
-He's fallen through the floor (not in this video sadly).
-He floated and attacked in midair.
-His SFA roll is not supposed to be invincible to everything.
-His hypers push you way too far to the corner. That's just not fair.
-His AI is too spammy. Just look at him.
-It seems like everything he does is safe on block. Even his hypers are annoying to correctly punish sometimes because they don't seem to have any recovery frames when landing.
-He starts off with an extra meter like in MvC. This is fine in the context of fighting other MvC EOH chars, but he's fighting a Ken that was designed with simply fighting Mugen characters in mind. See the difference?
-Is it just me or does nearly every one of his attacks shake the screen? That's just annoying.
-His lvl 3 Shinryuken (a bad conversion of one of his SF4 ultras) throws you behind him.
-He's walked before the round starts a few times. That's accurate-ish to MvC if that's the case, but some people need to realize that this is Mugen and not every character will have access to the same features.
That's all I can stand to write about him.