The first point is possible since any time you have a major change it can effect team dynamics but since Durant would cost the Warriors $26.6M and Barnes (if they match the Mavs offer) $23.75M you've really got to take the opportunity if it comes up. The second point depends on how you look at things, because if Durant comes to the Dubs I would expect him to be their top scorer. The way the Warriors are set up though with Curry/Thompson/Green/Iguodala as selfless as they appear to be, I'm not sure it actually matters. Initially, I was worried about whether there would be enough shots to go around but last year Durant took 1,381 shots and Harrison Barnes and Marreese Speights took about 1,100 between them so with a bit of creative juggling I don't think that would be huge either since if Durant comes I would be surprised if Speights came back and of course Barnes would be gone.
Having said all that, I would be absolutely amazed, poleaxed, gobsmacked if Durant leaves OKC.