One general suggestion that’s been brought up before, but probably not for a while: insert actors in real, physical clonetrooper armor. It it could be done convincingly, just a handful throughout AOTC and ROTS (at least in some backgrounds, but ideally replacing some in foreground shots) would go a long way toward making the films feel more tactile and making the CGI troopers more palatable.
I’d love to see a short subplot following a clone squad during Order 66 inserted. Something along the lines of Bad Batch or Seige of Mandalore, but shorter and more in line with the tone of ROTS.