I can't tell what it is exactly, but Flame Iori's animation seems just a bit "off" to me. It also feels like they mixed Iori's XII-style animation with his old school animations, without taking time to ensure they were consistent. I don't know, maybe it's just me?
Anyway, I'm still looking forward to him. But much more excited to see how EX Kyo turns out.
When I first saw him, I couldn't shake the feeling that he looks skinnier and a bit less impressive than the rest of the cast... Even Kyo looks more broadly shouldered with his large jacket! But I kind of like that about him, now; the skinny feel he has makes him feel more snakey, which fits with the "Clan cursed by Orochi" theme.
I don't much see the issue with the animations themselves (Clothes react just about right, his waist shirt has a bit more movement than normal, his rest frames in between rekkas could be a bit smoother, but are not bad), but maybe with the fact that the design is kinda "meh" for XIII. It's a classic, sure, but XIII is more about powerful presentation of characters. They recieved more weight, more strength. They became more significant looking. Yet Flames Iori feels so classic, that it's like he's stuck in time, haha.
This is probably fine for those who wanted the classics designs back / hate "bulky" Ralf and Clark, and "applebottom" Athena though, lol. But for me, it emphasizes why I really like the "larger than life" theme they went with for the characters since XII, rather than just a straight HD-ifying like those plain sketches from XII's development that so many claim to prefer.
I think it's fine to have all types in the new KoF style, though, and I appreciate differences. And it's inevitable, that as the art team changes, we'll see some shifts. But I hope their art team gets comfortable with shifting between the 2, so that characters who deserve the Nona-derived extremes can get them, such as say, Blue Mary, while those who could benefit from the whispier look, like Lin, could also benefit from that.