>>43900266And island that's pretty much another wild area, but with more diverse terrain.
There's a dojo where you train with Leon's old mentor. You get a new version specific rival to go along with the training. There's a bit of story.
You get to conquer one of two towers to evolve Kubfu, the signature legendary pokemon for the Isle of Armor.
There might be more than that, but those seem to be the main points.
Also there's more pokemon available and you can unlock gmax forms for certain pokemon.