I was kind of hoping for recycled Sonic stages given a fresh coat of paint, but after watching the gameplay trailer, it seems like they're giving old levels a fresh perspective as well. I certainly hope they don't screw this up. I personally don't like the distinction between Sonics. It was the natural evolution of the same character, much like the way Mario has changed appearances over the years. To create this division in characters and actually have two separate hedgehogs? It doesn't really make much sense to me.
EDIT: A little further explanation on my original hopes: I wanted to be playing City Escape with better graphics, for example. Original soundtrack and stage design intact. That would be the best game ever...A little side-scrolling Emerald Hill Zone, re-imagined artistically? Yes please.