Got a chance to play Ken in a Smash Ultimate Demo. Some changes that I haven't seen mentioned before:
No Red Fireball. Doing HCF B didn't seem to do anything. I could have done a mis input since I'm not used to pro controller but I'm fairly certain Ken doesn't have Shakunetsu since he's never had it before.
No Collarbone breaker. Doing heavy F tilt instead did this straight punch, kinda like Ken's Stand Medium Punch in SFV here:
https://www.youtube.com/watch?v=Ty5c4UCeivg#t=5s. Don't know if it does extra shield damage but it seemed to have a pretty good amount of knockback for how fast and short range it was.
Different Up-air. Ken's up-air is his jump Light Kick (SFV Animation here:
https://www.youtube.com/watch?v=Ty5c4UCeivg#t=2m30s).
Only got a chance to play with Ken in a 2 min FFA match so sorry for not testing out everything. I'm pretty sure his Heavy Uptilt, Light Uptilt, Heavy Dtilit, light Dtilt, Down Smash, Fair, Bair, Nair, and Dair are the same as Ryu, don't know if there's a difference in damage/frame data. I know Ken had a unique Kick animation in one of the trailers so he might have a different Upsmash than Ryu but I didn't try that out.