I want an Alolan Arbok too! I think it's deserving of one
Anon I could fill a (relatively short) book about Pokemon that deserve Alolan Forms. Arbok and Fearow have never been particularly great, I think they deserve one. In the same vein, Dodrio, Dewgong, Kingler, Parasect, Golduck, Primeape, Victreebel, Rapidash, and Seaking are all lesser used Gen 1 Pokemon that could use a serious boost. Even some more commonly used ones like Weezing could use a boost.
Additionally, Beedrill got a Mega, so I think it’s only fair Butterfree gets an Alolan form. Similarly, Gengar and Alakazam got Megas, and Golem got an Alolan form, so I think Machamp could get an Alolan form (although regular Machamp is still great). Jynx has been all but abandoned since Gen 1, I think she could use an Alolan as well. Dragonite is the only pre Gen 5 pseudo legend to not get a Mega, and it’s a marine animal as well so the fact that there’s no Alolan Dragonite is a bit of a let down. Starmie could also have a cool Alolan form, since something that evolves with Fire, Thunder, and Leaf Stones in Gen 1 (Ninetales, Raichu, and Exeggutor respectively) all got Alolan forms, leaving a Water Stone evolution out.
When the original Sun and Moon came out I was pretty disappointed at how few Alolan forms there were, and I’m really REALLY disappointed that there’s no new Alolan forms in USUM. I thought new ones were all but confirmed as soon as the concept of the game was announced and I’ve been waiting every day since for an official confirmation, I never thought they’d just outright not happen. With that said, since they don’t seem to be doing a demo this time around, it’s technically possible (but rather unlikely) that they do have new Alolan forms and are trying to keep it a surprise, so I’ll withhold judgement until we get the facts, but that’s my stance that I only now realize you did not in any way ask for.