So supposedly they got the level designer from Sonic 3 working on this. I'm too lazy to check 55 pages to see if it's already posted, so fuck y'all I'm posting it anyways:
http://www.destructoid.com/sonic-3-level-designer-is-working-on-sonic-the-hedgehog-4-164382.phtml
I dunno where that guy's been for all these years, or if he's always been around and his work's gone downhill, but it's interesting nonetheless. I'm still salty about the homing attack, though.