I feel like people misinterpret what another Sonic Adventure actually means. It's as if them attempting a third game means they'll automatically take the worst most unfun aspects of the franchise and create some kind of 15-hour Big the Cat fishing Campaign travesty starring a playable amy, blaze, silver, suck the cock, froggy, poochie, maria, and the duke of soleanna, with no collision detection and hours of unskippable cutscenes.
No. Like I've repeated before, I can can very much see another Adventure focusing on just a playable Sonic, Tails and Knuckles. Levels that are less "racetrack" narrow and more open to exploration. Maybe a light Unleashed-esque plot. The Sonic Team of melodrama, incompetent programers, zero QA and 100% necrophilia is very much gone. I'd love to see them take another stab an Adventure, having learned all they have with their fresh new team. I'm also pretty much fed up with the current racetrack Sonic. To me they've come closest to doing Sonic justice in 3D with the original SA Sonic, so to see them try and build off of that interests me.
Although I think I'm in the minority with this opinion anyway.