Zeb always kinda sucked and his "generic surly tough guy friend who's a grouchy hardass normally but is secretly a gentle giant with a heart of gold" schtick was really tiring and Rex should've just been "the tough guy" member of the Rebels crew from the start, he's a way more interesting and layered character

Rebels should've just been "The Hera & Kanan Show, also Sabine and Rex are there too and Chopper is a gremlin R2D2"

Ezra gets a pretty good development and arc eventually be he's such a damn wiener kid initially and I also always thought Kanan and Hera should've been the protagonists

Also whenever Ashoka's not on the screen, all the other characters should be looking around asking, "Where's Ashoka?"

In conclusion, the galaxy far, far away is a land of contrasts