For several years now I've had this growing suspicion about GF moving away from working with long-term plans in mind (to be fair, maybe they never had any to begin with) to a more improvised game by game approach, as well as moving away from believing in their own vision of the Pokémon world to an increasing nostalgia milking fanservice focus.
When you revolutionise the idea of follow-up games with BW1->BW2, and then next gen basically skip the concept entirely for XY (jumping straight to SM with no real connection), you got me baffled. Add the fact that their recent marketing strategy reveals essentially everything about whatever the next game is leading up to its release, and you get a hype that builds too long and too high and dies too fast after.
Perhaps they're intentionally trying to constantly be surprising and new now rather than being consistent and adding twists into a more predictable thread, but as it stands right now, I have absolutely no clue what their next move is, which for some reason, for the first time in the franchise feels like a bad thing to me.
What I do know however, is what kind of game I hope they are NOT making.
1. if it's a straight jump to Gen8
I'd rather it not be a third small, exotic, isolated generation in a row (way below 100 new Pokémon, mostly fancy type combos, no cross-gen evolutions or direct ties to old Pokémon, but have the regional dex filled with "classic" Pokémon to the point where the new ones are a rare sight. Let's not forget a new feature that adds new designs for mostly if not exclusively gen1 Pokémon...). I'm of course dying for another BW-like generation, but I would also be really really fine with a smaller generation IF it was more akin to gen2 and gen4, not gen6/7. gen 2/4 were "complementing" what came before them, building upon it, in contrast to bold and new sort of "reboots" with gen3/5. I feel like if BW was one end of the spectrum, XY was the extreme opposite, but despite that, SM somehow managed to amplify the concept even further. If a third generation like this is up next, pleeeeaaase at the very least make it related to SM (if not XY as well) rather than going somewhere completely unrelated again.. I mean, make it a second set of islands and make it sort of a counterpart to SM while being a sequel to it without featuring Alola itself in it. Expand the core concept of Alola formes, ditch the gen1 focus. I'd be on board the hype train instantly. But if it's an all new story in an all new place, with no ties to anything (except Kanto lol.), while having Necrozma shoved into the middle of it with no real relevance or connection, I'll be quite disappointed to say the least.
An SM follow-up that isn't also a new gen is IMO out of the question, so I'm not even listing that separately.
2. a simple "remake" game. Sinnoh....or heck, possibly even a Kanto revisit
Whichever it would be, STOP THE COPY-PASTE APPROACH. The "remakes" so far have hardly been improving (I mean when you take away all the ways the actual main games set the new bar in its generation). Quite the opposite: since the main games have been getting bigger and deeper every generation, as well as their follow-ups more serious, the development of their remakes is getting more and more reduced to the necessities. It's my favourite region, but I don't want to travel through a Sinnoh that's near identical to DPs version of it just after SM got rid of the grid-aspect of the overworld design for example. I don't want to see them re-tell DP specifically either, pretending like Pt didn't happen, and try to make up for it by adding a "Platinum episode" where we take a walk into the Distortion world, catch Giratina with a lame catchrate and have to fight Arceus right after or something like that... same in case of a Kanto revisit. We've been to Kanto 4 times. It's unacceptable to not do something drastically different with it the next time. So my point here is basically, do something very refreshing (20-years-later sequels, or redesign their region from scratch and play around with a lot of things they resisted changing in the past remakes) or don't do it. Don't try staying true to the originals too hard, I don't think changes would piss fans of the originals off as bad as you think..
I really want them to get me back on board. GAMFREAK, BLOW MY MIND PLS
I doubt they would do 8 minutes for just a mobile game.
I'm willing to bet this is "Pokemon Stars" or a DP remake. Though I will literally take anything.
The bigger question is if it's a Switch game.
There is no way the next main installment would suddenly be a switch-game. A 3Ds game that also releases as a Switch-ported game at the same time? Sure, but actually developed FOR the switch from start? No.