I was told somewhere (not sure if it was this forum or the discord) that the reason games from gen 6 or later gens are not likely to be ever added is because of three main limiting factors:
1 - Pokemons from those games no longer use a sprite system (or at something like that)
2 - Adding custom made sprites would void the terms under wich Nintendo turns a blind eye to this game's continuation, because they DO know and I'm pretty sure they're waiting for even the slightest chance to bonk it out with a cease and desist (effectively so this time since the creators would be altering assets from their IP)
3 - It would be a massive endeavor to actually implement the Gen 6+ mons and regions as they are, and said endeavor is not likely to be take on by a small dev team as PokeMMO's
Did I get it right or is there something I'm missing out?