AFAIK the changes to stock are:
Added gimbals to all engines except RT-5 Flea
Redone all models, made gimbals realistic, better textures, no glitchy colision, some new features
New engines and parts, all in line with stock
I understand what you are saying though, while IMHO it is just a better-looking stock you might believe that the 'Nova' engine for example is too cheaty.