>>43518990I don't like LGPE, but I think it's neat that it's kind of a sequel instead of just a remake. I'd want something like this for Sinnoh.
Let you play as new characters (also work better with the customization feature). Have Lucas and Dawn as adults be the game's professor and champion, switching their role depending on what gender your protagonist is. Put Cynthia in the post-game and have adult Barry take over his father's role. You can keep the story mostly the same, have Team Plasma be reformed after the admins left jail (broke out or served their time) and they're seeking the cover Legendary's power because they think Cyrus is imprisoned in the Distortion World, not realizing he chose to be there.
If they want to put in gen8 features, have a meteor fall on Mt. Coronet. This partially destroys it/changes its layout and part of it is now a rocky Wild Area. You can still have normal caves under it. You can also use this as an excuse to say it changed the ecosystem or something to change other areas and expend the dex.