I haven't heard anyone saying that Switch would be a remake. I heard people theorizing that after SM we'd get some kind of 20th anniversary game that either remade Gen 1 or revisited Kanto for a new adventure, but those theories were geared towards another 3ds game.
That said, obviously Switch will be Gen 8, but it *could* realistically be a revisit of a previous region or something of the like. Yeah, a new region is more likely, but for making the jump to a full-on console (despite the fact that it's also portable) it wouldn't be out of the realm of possibility to revisit the roots of the series as a sort of "See how far we've come" thing. If they want to go back to Kanto and create a new story set 20 years after the original games then I'm all for it. I'd love to see what two decades could do to the place. Safari Zone probably has a lot more exotic pokemon these days, Saffron is probably a sprawling metropolis of tech, Celadon is probably gorgeous and covered in flowers, etc. etc. I'd just be excited to see a return to the beginning so to speak. That doesn't mean it won't be Gen 8, just that it'll be in a familiar setting.
More realistically though, we're totally getting a new region and a handful of new pokemon native to it. I just really hope they keep regional variants as a thing. I'd love to see some fresh takes on old faves to pad out the new mons.