I think it's rather impossible to know which promos are scripted and whatnot. I think we can be pretty sure that guys like Rock, Undertaker and Triple H largely have their own input. Rock/Cena probably did too as a feud, but it seemed obvious to me that Rock was holding back to an extent. CM Punk has a lot of creative leeway from what I've heard but most of his promos are scripted, too. He really disliked the creative direction of his feud with Taker at Mania 29, for example. People also thought his "pipebomb" on The Rock back in January was all his own doing but it came out (unless my memory is wrong) that the only part of it that was 100% Punk was the part where he talked about Daniel Bryan having to fake a comedy gimmick for the benefit of amusing certain people backstage (this was my least favorite part of the promo since it, once again, nearly broke kayfabe ON-SCREEN, which is a no no.)