The best thing about Ken is he's receiving no known nerfs as of yet, only improvements. It's still unconfirmed whether his sweep is faster, but his cr MP does have more hit stun, and probably active frames. Confirmed he can Cr. MK, Hadoken, FADC U2, but U2 scales the damage quite a bit. Target combo might of received improvement, it's definitely better than it was before. Hadoken is also slightly faster.
And in the build I was familiar with, Ken's MP Shoryu got a significant invincibility increase. I've been hearing tons of things about his HP shoryu, but didn't see any of it when playing. For example, with the new invincibility frames on MP Shoryu, you can consistently hit Akuma out of a Demon Flip Dive Kick. In SF4, it was always a trade or would go in Akumas favor. Now, it's free damage for Ken. That alone is pretty big.