According to moviecencorship it's mainly just dialogue that's cut
Scream 4 (Comparison: Theatrical Version - UK Version / Pay-per-View Cut) - Movie-Censorship.com
Why ? Don't get idea of cutting and adding deleting etc odd word here and there especially sometimes if it isn't swearing or offensive words,
Ps yes the editing was bad in the barn scene where he stabs Gale he didn't even touch here and it was very noticeable,
Well more of hitting at the side with a joke knife that slides in, either way he didn't touch / stab her