But here's what I theorize the next Sonic game will be, based on this cycle, context clues, and falling in line with but not necessarily fully basing it on leaks:
Sonic Team tries to bring the Mania formula into 3D. Seeing as the level designers now have one formula to focus on and not 3, the level design is better than Forces but not quite on the level of Sonic 3 or Mania. I think it's going to get the terrain correct since those parts of the stages have always been done well since Unleashed, but the object placement is probably going to be terrible, and the different elements of the level design (Speed, platforming, exploration) are going to feel incredibly disconnected from eachother.
The physics are also just definitely going to be less than stellar. Not quite Forces, but not ideal. Maybe Spark 2 is a good example, but heavier or floatier, and probably a little stiff. He'd also likely have Adventure moves but they'd fuck it up in some way, like a bounce bracelet that stops all of your momentum or a slow ass homing attack with a delay before you can input after using it, and of course the mash-spindash for nostalgia purposes (it would suck)
Say it with me folks, 2D sections, wisps, and only Sonic playable. 2D sections because it's easier on the very few level designers that they have (We might see better level design in 2D than 3D but I wouldn't count on it). Wisps because they're a core part of the Sonic brand identity at this point, don't expect them to be in the plot or feel good to use (Although they could actually benefit the level design a little by opening up new paths seeing as classic levels generally have more full paths compared to modern level shortcuts). Only Sonic playable because they're trying to please people who don't like the games in the first place.
And let's talk about that story. They'd likely go for Adventure nostalgia and entirely miss the mark. Think Episode Shadow, including the really shitty character motives and parts that just outright don't make sense.
As for the art direction, you really can't predict about this, but I think enough people on the team would see this as a "Comeback" for there to be a decent budget.
So would this game be well-received? yeah would probably be the best received 3d sonic game in years
Would this game be good? probably not great but i mean yeah it'd probably be fun