If honesty is what you truly desire, you must acknowledge that what's "good" and "bad" in gaming is purely subjective. "One mans trash is another mans treasure" as they say. I could go on a long rant about why I feel like hub worlds are a good idea for 3D Sonic games if handled correctly, but someone else's opinion that they should stick strictly to 2D menus to navigate from level to level is equally valid, as is someone else entirely with their opinion that the progression should be automatic like in the old Genesis/Mega Drive classics. You or I may consider Superman 64 to be genuine garbage better off in a trash can than inserted into a console, but someone out there might consider it their favorite game of all time, and that's okay.
Sonic 06 is a game that had tremendous potential that ultimately the majority of which went wasted. It's neither the first or the last game like this in the franchise, but it is probably the biggest offender. Considering we are not living in a version of history in which the game got the proper love and care in development it deserved and a delay or two to smooth things over, to say that we know for sure how the final product would have turned out under ideal conditions is frankly quite absurd and silly.