>>25235520It's nothing but the Maison and Legendaries. There's only one battle facility and it's literally just the French Battle Tower, and there aren't even any new dungeons for the Legendaries you can catch, Heatran being the exception.
HGSS has Platinum's Frontier, Moltres/Articuno/Mewtwo have new dungeon-like areas to traverse, it has Gym Leader rematches, there's a ton to do.
And if you're going to try calling the Delta Episode postgame, then that would mean Kanto is also postgame in HGSS (I consider both part of the main game) so it pushes you out even more.
BW2 also has more postgame than ORAS, like the other anon explained.
Emerald has more REPLAYABLE postgame, too. I need to make that distinction since I know shitposters like you always say "it takes more battles to 100% the Maison than the Frontier because the Maison makes you do the piss-easy mode for each format five times!" while the Frontier has seven. Legendaries are a one-time thing, after you've walked to their location without obstacle and caught them you can't do anything with them again. I can have a greater variety of battles in the Frontier than the Maison after I've gotten all the cheevos from both.