My biggest thing is that he'll be too much in KD's face, I mean i hate the whole "leadership by example" crap they say KD does and no one holds him accountable, but cp3 can be a lot for arguably a top 5 all time player to deal with.
I didn't watch a lot of Warriors games outside of when they played the Suns but CP3 never got in Curry, Klay, or Draymond's face in a confrontational manner. I don't recall him doing that to KD when they were together for those 25-30 games last season also.
CP3 has this reputation that supersedes his actual game. He's supposedly this big bully who is always berating his teammates and flopping into guys to hurt them as well. I didn't see that in Phoenix over his tenure and I didn't see that in Golden State. He did ride Ayton occasionally but Ayton needs someone riding him. I won't use that as an example of CP3 being a bad teammate because Paul wasn't the only one who did get on Ayton's case for being disengaged or making boneheaded reads.