Compared to Witcher 3 the GTA V isn’t even a game, especially if you look at the extremely rigid mission structure in otherwise open world. Rockstar wants to tell stories, not make games. I can’t understand why they just don’t turn into a movie studio at this point.
I can confidently write this, because I’m currently playing through GTA V story mode.
The aesthetics are not so much even about the engine. It’s about design.