>>720156526
>Were they replaced by another secret team at Sega?
Frontiers was just as mediocre and flawed as Kishimoto's other games.
Shadow Gens was directed by one of the main designers who worked on Generations (funnily, another game not directed by Kishimoto).
Crossworlds is largely being done by Initial D devs, iirc. Sonic Team is just supervising and providing assets, like with pretty much every game they don't directly work on.

The next Sonic game will be directed by Kishimoto again, so there's no reason to expect it to be anything more than fundamentally flawed in several areas it shouldn't be. Again.
That's just the nature of this IP. The quality Jap devs move on to work on more Japanese-relevant franchises, while the mediocre/good enough devs stick around on Sonic. Thus, a never-ending roller coaster of quality.