SAB-CA did you fight with or against K' much? Did he seem visibly nerfed?
How about Saiki? Did he feel balanced or potentially overpowered?
I played K' very little myself, and the people that played him didn't make him feel any better than a Kyo. Most people who played K', Kyo, or Kula, were much more comfortable with the latter 2, than the former.
When I played him, I didn't feel particularly great. I liked other people's hops better (very weird, I love Lin's Hop D in 2k2UM, K' shoulda been similiar, but it just felt GOOD for me, not stand-out fantastic), and the fact it lost crossup properties was kinda funny (it's easier to cross up with Terry's Hop ;D, and lets not even mention Takuma's!).
I'm confident he would have felt strong, if I took the time to get comfortable with him on those sticks, but I was much more interested in playing characters people don't see all the time.
Saiki... I had more problems with Ash, than Saiki, TBH. All the little flame kisses on screen, the great zoning tactics, the deft movements... at the quality I played him / others played him, Saiki just felt like a poor man's Ash, lol. I tried him once, lost miserably, and decided if I was gonna play somone new, I'd stick with Billy, instead. I could see Saiki working great once you learn his in's and out's, but with so much move versatility, it was really easy to drive cancel on accident, or waste a DM doing something at a time where most characters wouldn't HAVE a cancel.
Billy ALSO felt weird, as his staff's priority and "hurt" zones felt much different than I'm used to with him. I wanted him to provide meaty coverage for himself, kinda like Whip, but instead, he seemed very much like he needed to aim his blows percisely. And he wasn't masher friendly at all, leading to a lot of un-intended staff twirling. He seemed to go into said blows much easier than Clark or Joe, which threw me off a few times.
I wasn't THAT comfortable with my Chin play, but I had more people screaming that he, Hwa, and Maxima were cheap, than any other K' or Kula's. The new changes to K' uppercuts made the old Minute Spikes combos awkward for many, and since pretty much everyone I play can grapple, his more-punishable recoveries lead to quick deaths for many neophite-K's.