>>46235756I think the thing with Unova's routes is less that they have optional areas, since as you said, both Hoenn and Sinnoh had them, but more than almost every route had them as opposed to a small handful of midgame routes.
Even Route 1, which in every other game in the series serves as little more than a tutorial area with absolutely no reason to return to it outside of the occasional forced backtracking, has two sizable routes connected to it that you can only access by returning later in the game.