>>45135869probably because it'd be way too hard to justify weird metamorphic stages without completely changing how evolution works in-game
Koffing With A Boil doesn't really have a reason to exist as a distinct state with its own movepool or stats, but if it was more gradual across the board and pokemon slowly changed forms every couple levels until they hit the next "stage" then maybe it'd work better and not feel like filler just to being every line up to the max three stages
