Sonic Mania is releasing early 2017 with many Sonic fans excited about this project. Recently a stream was released where it was announced that Sonic Mania would have more re-imagined zones compared to original zones.
Meaning, we will get more remastered zones over original zones like Studiopolis. While one might see this as an issue, it was confirmed not long ago that Mania will be longer than Sonic Generations (which had 9 zones, 4 bosses, and 3 rival fights). 
We will likely learn more about this recent announcement in the future but stay tuned to 3WIREL for future Sonic news!