Based on what they've said they're doing, they're actually going away even further from the classic locations like jungles and volcanoes, they've said (as we all know) the levels are going to be based on real life locations, we've already seen the levels, High Europe and Greece, and for a sonic game I just don't think those locations work much, however I like the look of China, and there's a desert level which could look very retro.
Also, noone else on any other site seems to have noticed this, but there was an interview with one of the developers, and he said after each level you go into a town and buy upgrades such as better acceleration and faster side dashing, this screams crippled sonic from the secret rings for the start of the game to me. Funny how this critical information which could decide wether this game sucks or not is hiddeen in one interview, but its strange noone esle has mentioned this yet.
Basically the trailers are once again a lie and Sega have forgotten to mention one really important screw up, this time its the fact that we're not going to start with the speed shown in the trailers and we're going to start off slow like secret rings.
This finally explains to me how we're meant to take different pathways our first time playing through, when I was watching the High Europe trailer, I was thinking "how are we supposed to react to that wall jumping shortcut the first time playing through when we run so fast past it? The answer is simple, you'll be running slowly with a downgraded sonic at the start of the game so you'll easily be able to see it when running through the first time, and you can then jump up, and when you finally buy all your abilities and get to full speed you'll have memorized the level, it makes perfect sense, welcome back crippled Sonic from Secret Rings.