It would probably help if Sonic fans could admit that Sonic Adventure really isn't that good. Yeah, Adventure 2, Heroes, Shadow, 06, Secret Rings, Unleashed, and Black Knight were underwhelming, but without the nostalgia goggles, all of them were as good as or better than Adventure. At least none of them had any fishing levels. Everyone acts like Adventure was the holy grail of 3D Sonic that we need to reclaim, but they don't realize that the reason no game lives up to Adventure is because they're only comparing it to their own idealized mental image of Adventure from when they were eight years old.
I do have to give Sonic Team credit for always trying something new -- they haven't hit gold yet, but if they keep going somewhere different each time, they've got to find something eventually -- and for keeping the 2D series going in the meantime. Still, Miyamoto should at least come in and show them how to make a decent camera system. After ten years, it's just inexcusable.