The problem is, we know what all the Zones in Sonic 4 are already. And they are all rehashes. That said, they probably play out quite differently, and the addition of the homing attack will certainly mix things up. But no Sonic game has blatantly stolen from it's previous games as much as this (not counting gamegear and Sonic Pocket Adventure).
But, this is just Part 1. I think what we'll see is that this game will be the one without anything really original. I think they'll try to mix things up a lot more in the coming Parts. But I just think it's a bit lame to hype the hell out of the first part, and then have there be nothing new about it.
And do not count on a Crush 40 song in this game. I just do not think that is going to happen, based on the music we have heard, and how retro SEGA is trying to make this (and their apparent lack of effort so far). However, if they DO make a new track for the game, there is now truly only one song that will work.
Sonic Boom - Crush 40
To quote Jaleel White, "I'm waaaaiting."