I actually think Sonic 4 (and colors) both give you quite a bit of freedom. There are parts where it's on-rails and your path is set, but for much of both games your own skill determines which path you can stay on. The highest paths are the best and filled with all the good stuff, but they're the most challenging to stay on and require accurate jumps, timing, etc. Certainly, neither Sonic 4 or Colors are as on-rails as games like Secret Rings or Black Knight, so I think the trend actually goes backwards in favor of exploration and freedom with both games. For the future of Sonic 4, it's still too early for me to confirm anything regarding the next episode, but I am passing on all the feedback. I agree with the many of you who would love to see really classic style gameplay again, and am pushing to help get it some attention with every opportunity I can.