Why didn't Bully return
This would've been a straight gold mine for him and his career he could've pulled Emmys every season and doesn't have to be a villain either
shareBy "Bully", I suppose you mean Billy Bob Thornton.
The reasons he didn't return were :
(1) Season 2 took place 27 years before season 1, so no actors returned for season 2 (but a few characters were in both -- played by younger actors).
(2) He can't return for season 3 because his character died at the end of season 1.
(3) Besides, each season tells a totally different story (albeit with some thread connecting the seasons), and they seem to want to always have all new actors from one season to the next. So even if Billy Bob was willing to come back, I think the producers would have continued with the "all new actors" route.