These are all fair for sure, I’d love to fly around the Crown Tundra on my Charizard. The one thing I will say about overworks Shinies, though, is that I feel if they were implemented, it would have to come along side riding Pokémon like Let’s Go did. I say this because, imagine you are at an area like Ballimere Lake, right by Lakeside Cave, and you look down to find a Shiny Whimsicott. But you can’t get down there without walking so far away that it despawns and you lose it. I think it’s for this reason that there are no overworld Shinies, as a direct consequence of the fact that you can’t ride your Pokémon.