Only the gullible buy into the "complete engine rewrite" bullshit, if anyone has ever looked at the internals of a Rockstar game they always bolt on top of what they've done, it's been like that since day 1 with table tennis.In what world is a complete engine rewrite, increased physics and damage models, 100+ new music tracks, AI and density increase and fucking VR support "underwhelming"?
What else were you expecting?
The most it could be is updating the engine build from GTAVs to the one RDR2 used which has a few extra graphical features.
Physics and Damage code is already there, it was toned down from GTA IV.