I wouldn't get my hopes up.
Honestly if/when the Gen IV remake comes I can see them just completely removing the post-game island as a whole and gimping the underground (how about no secret bases there too). It wouldn't be surprising or anything, they've been removing shit senselessly for multiple gens now.
I was thinking about this when randomly looking at the Kalos map the other day. It's so big, if they had just cut off a portion of it to be post-game content, no one would say the game is unfinished. But because the entirety of it is main game, people think there's no content. It's just the life of Pokémon fans to judge the games solely based on the post-game stuff.
As I said before, as much as X/Y did leave some loose ends here and there, it does deserve credit for doing essentially everything Sword/Shield aren't - that is, to bring over the entire national Pokédex into 3D, making over 700 models and several animations for each, including new cries for all of them and many variations of each cry that are only there to be used in a mini-game of all things. All that, on top of having the lengthiest campaign and largest region of any Pokémon game to date, makes me think not too highly of people who say those games were lazy or half-assed.
Everything that came after, though... yeah.