Nah. Not a fan. For all the 'no new ideas' type stuff that gets thrown around every time a new set of pokemon games comes out, this is a new low. It's literally not a new idea. It's just taking an existing beastie, and slapping a new type and colour onto it. I realise that's not 100% literal, but Vulpix/Ninetales are almost entirely white versions of their old selves. Whereas Sandshrew/Sandslash just look exactly like I'd expect having given an artist the brief 'Ice Sandshrew/Slash'. The only one that I can somewhat buy is the palm tree shift for Exeggutor, though the shift from Grass/Psychic to Grass/Dragon is weird and somewhat pointless imo.
It's not even 'evolution' across regions. That's not how evolution works. At all. If this was evolution, it wouldn't be a 'variant', it'd be a new species. Actually making an Ice pokemon with a fox aesthetic? Yeah, I could buy that as an evolution (still probably not, because a fire type in an icy environment would most likely just die, no reproduction, therefore no evolution, but still, it's closer). A white Vulpix that's still identified as a Vulpix? Just plain nope.
And does this mean that we won't be able to get the proper versions of these 'Alola' variant pokemon without trading from older games?