I feel like this subject has been brought up before, and I'm sorry if it has, haha.
Sonic Mania is shaping up to be the return to the basics that all of the more nostalgic fans wanted all along. From the gameplay, to the characters, to the graphics, to the music, to the stage elements... the overall TONE is there. Sonic 4 missed the mark big time, and Sonic Generations, while fun, was still missing something.
Sega enlisted the help of some well known hackers to create the game, and it's working well for them. They really seem to understand what made the originals great.
Donkey Kong Country Returns and Tropical Freeze were swell, don't get me wrong. I loved those games. and I respect the fact that Retro wanted to do their own thing with the series. However, I and a few others wouldn't mind seeing a game in the style of the old trilogy (albeit a little updated).
Retro's busy, Rare's doing their own thing... Playtonic is theoretically an option, I guess.
Anyway, I've wanted something like this ever since Megaman 9 came out.
I would very much like Donkey Kong Country 4 -- but I'll settle for playing Returns and Tropical Freeze for now. (Also need to get my hands on some good hacks/fangames).