After playing Generations(PC and 3DS), Colors(DS), Black Knight, Secret Rings, the lackluster 3DS Lost World demo and watching lets plays of other Sonic games made in the past ten years, I've realized Sega still has no idea how to handle a 3D Sonic game and can't find a decent direction for the franchise.
In Generations, playing Genesis era stages is usually fun for both Sonics, but the fun level hits extreme turbulence in every act based on post Genesis games, especially as modern Sonic. Generations also had IMHO poor choices for stages from Sonic's past. I loved Hydrocity Zone and other cool places, but they gave us really bland looking places instead and poorer layouts than the originals.
The games just have too many gimmicks put in to try and keep him relevant. The Colors gimmick was neat but in both version the level design and how you obtained those powers hurt the games overall. The view for his speed in every game is also horrible. I just want a classic styled Sonic game with no stupid ranking and ridiculous amounts of springs patterns/boosters throwing you around and not giving you enough time to react. The Advance series was the last to deliver on this, they ruined that by shoehorning in the loads and loads of characters that Sonic Team needs stop thinking we like as playable characters or even seeing. Sonic 4: Ep. 2 fixed the physics problems with Ep. 1, but it failed to sell good enough to warrant more episodes since they released a game right before that had touched people in a place or in a way that made them feel uncomfortable. And that's no good.
I have waited for any recent Sonic game I wanted to drop in price since the Adventure era, and the amount I'm willing to pay is getting lower even as Sonic supposedly is making a slight comeback. Sega, you better make this a good game. I'm not holding my breath, though.