It's not as bad a game as some say, but because it's such a let down compared to what a 'Generations 2' or a later game should have been, I'm not going to rate it higher.
After finishing the story, and feeling so disappointed that this wasn't a step up on Generations, I'm not much interest to go back and play it more. (Classic Sonic also seems to have some physics issues that weren't in Generations). Forces' gameplay feels much more 'on rails' and the levels are much shorter. Running at 60 fps, Sonic has never looked better.