I have to say, it really feels like they've been struggling for new ideas for designs with Pokemon ever since they've just started revamping old Pokemon with mega evolutions, and now there's new forms of older Pokemon. I do actually quite like the new designs so far though, and I kinda expected something like this to be introduced for years ever since they made gender differences between some Pokemon in the 4th gen.
This begs the question though, are ALL Pokemon that have a different form in the Alola region, going to be that form? For example, are regular Vulpix going to exist alongside the new form? If I were to transfer a Sandslash from an older game into this one, will it suddenly change into an ice/steel type? I certainly hope that isn't the case, and I see no reason why the forms can't co-exist alongside each other in a single game, but it's gotten me wondering nonetheless, and I can't seem to find the answer to this anywhere online yet.
Pretty sure this will only be ones that you find on the islands.