Here's the thing: from what I understand the speed and platforming, for all intents and purposes, work well enough in most of the 3D Sonic games. The problem is Sonic Team is trying to set that up against concepts that are not what the character is about (ie: werehogs and King Arthur). It's as if they're just trying whatever they think works without considering the fact that it's a Sonic game first.
The real solution to this problem is simple: the Archie Comics Sonic the Hedgehog series. For a comic book series that's been on-going for over 200 issues (not even including the spin-offs), it's clear that something is being done right. I only have a few issues of the early stuff, and it still holds up. Sure, it's mostly based on the SatAM series, but my point remains the same.
Dear Sonic Team,
You have a gold mine of source material at your disposal. Use it. Or continue to fail as a developer.
Punch-punch-go, Jbird.