People like satured colors. Honestly I'm not fond of it. I don't see anything bad in less saturated colors. Is more realistic and less fake. What KOF needs is not more vibrating colors, but some fine hue. Like a bit of magenta/cyan in shadows and yellow in highlights. That gives a nice feeling. SFV i just ok, it doesn't need that retouch.
As for Kyo and Iori, I think it's pretty obvious that they where done at the beginning of the process, and Benimaru maybe it has been done later, after having some more experience doing other characters before him. Or at least this is what it looks like. Benimaru is really well done and polished.