We already got that with Origins.
Origins has functionally different characters for the most part. The original Pokemon anime - and also recent seasons I believe - adapt characters more than translate them. So you get Ash who is very different from Red, and even the anime versions of characters like Misty, Brock, Gary, Giovanni, and more who are decidedly different from their game counterparts even as they pull from the same base.
There is an interesting story to be told in the original anime with a slightly different original premise, I think. Does Ash become Team Rocket's rivals if he doesn't have a "special" Pikachu? Does he run into Misty in the same way? Does he beat Brock easily and not recruit him on his journey?
This just looks fucking boring though, it doesn't give me an interesting retelling of elements I care about from the original anime. It's missing the point - original trailers were shot-for-shot recreations of scenes from the original episodes, with some twists and implications for some alternate plot. But instead of having a small, interesting twist to explore, it seems like they just went off on some other random direction and only really used episode one of the anime as any sort of basis - and even ignored parts of that, seeing as Misty is absent. And, again, missed out on one of the most iconic and memorable parts of the anime's first season, the companions. Bad, bad move that leaves a sour taste in my mouth.
Also it's super disingenuous to call it an origin story when it's barely based on Ash's original journey at all.
Also, to everyone saying "if you want a remake, go watch the original", there is no original movie adaptation of "Ash's origin story" or any of the original anime for that matter.