well that's easy, none of them because when you're ignoring all game mechanics, characters, maps, gyms, graphics, et cetera it's just a bucket of stats. what the hell kind of excitement is there when there isn't even pikachu
though if we're really gonna do this probably gen 5, because by itself it was actually a pretty balanced gen, with very few spikers and literally only one reliable toxic user. the legendaries also weren't ridiculous either and didn't make you want to kill yourself. playing solely unova tournaments felt really fresh and new and nothing felt horribly OP because heck even EXP gains were unique to that gen allowing for further balancing of like...
level-specific cups not feeling terribly imba, either. everything was just...nice and chill af
that and you also didn't have 10 year old linkin park coolkid shit like deoxys or darkrai or arceus
though if we're really gonna do this probably gen 5, because by itself it was actually a pretty balanced gen, with very few spikers and literally only one reliable toxic user. the legendaries also weren't ridiculous either and didn't make you want to kill yourself. playing solely unova tournaments felt really fresh and new and nothing felt horribly OP because heck even EXP gains were unique to that gen allowing for further balancing of like...
level-specific cups not feeling terribly imba, either. everything was just...nice and chill af
that and you also didn't have 10 year old linkin park coolkid shit like deoxys or darkrai or arceus