Game development I'd be certain is nothing like how it was in the days of Sonic CD, so I'm not sure how useful it may be to bring them back to may a new Sonic game.
I love Sonic Team, they are the only ones doing what they are doing, as much as they are screwing up they have no competition. There is only one Sonic.
If Sonic has been such a disaster I would wonder how come no other developer tries to make a Sonic clone? I actually don't know why but I would wonder. But I could say it just furthers my point.
In fact I wish Sonic Team had the rights to other company's franchises, not the opposite. A Sonic Team Megaman or Sonic Team Mario, or Sonic Team Star Fox, are all games I have fantasized about. They would undoubtedly be very interesting games. Megaman would finally have a respectable mainline console game with decent graphics (oh and it'd be "3D" some say this 'peripheral' third dimension just a buzz word but I think it has potential) Mario would return to action instead of puzzles, and Star Fox will finally get another flight shooter and retain the pep of SF64. Really it's hard to say that Star Fox or Megaman are even in good hands to begin with, though I'm certain someone is now going to argue that against me.
Really the thing I generally wish for terms of Sonic development is that they simply do a better job next time.
And I also wish they take care of the stories better. Not saying the stories are bad, they're GOOD on paper. But they need better actors, story needs better flow, they should take a few lessons in more western style and movie style of presentation and structure, I would think. Since the Last Story in Sonic and the last boss itself is lame... I would think that the last boss is rushed but the entire Last Story feels cheap. I just don't think that kind of crap would find its way into a Disney flick. Imagine, they could have made the 10-years-ago scene with Shadow and Silver actually feel emotionally compelling and pivotal.
And to respect the universe more. The town missions have Shadow driving over generic civilian cars as tall as he is with an oversized buggy (with nitros) in a sanctioned race. Come on.
Failing that they should do what I mentioned in the Game Ideas thread and make a storyless game and just stick to the fundamentals of the gameplay, and the franchise appeal which stands with or without a story.
Sonic showed us so much and still has so much potential.. many franchises could have done similar to what Sonic has. Sonic Team is the only developer who went in this direction. They did Radical Train. Nobody has ever done anything like Radical Train. If another developer got it, what would we have? We'd have Ratchet. Or Kameo. That's what I've always said I'm concerned with when discussions like these arise. To conclude my point I could say that Sonic Team has failed, let's say they have, but then there is nothing else like Sonic in a long time.
*scratches back of head* >_>
edit: oh and I forgot to mention, CD and Sonic R? You may kind of be alone on this one. I personally don't think either game is bad of course but actually I went back to play both on Gems to find that neither is as good as I remember it. (especially CD, frustrating time mechanic) Though then again I'm sure anyone else can say Sonic Rush which is also sort of by Dimps and loved by all, though you didn't mention it.