flexing mod muscles:
I think the title debate could go on and on til we're blue in the face (hey, just like Sonic!), so I think it's best if we either let it rest or simply have our say on it and not move into a quoting match. Besides, this thread is 164 pages as is.
Sound good? Cool.
My take on it: Sonic '06 had the audacity to proclaim that it was the return of "Sonic the Hedgehog" to the gaming world. Using the original title of the Genesis days to basically say that Sonic '91 was to the 2D world as Sonic '06 would be to the 3D world. Of course, such a bold statement was a failure as the game not only did not live up to its title, but it was also a terrible game on its own. Any title could not save '06. Funnily enough, Sonic '06 is almost never even called "Sonic the Hedgehog". It was so bad it was stripped of its true name and was given a prison number (2006).
Now we have Sonic the Hedgehog 4 Episode 1, a game that once again has the audacity to share a name with the original classic series. However, unlike '06, it isn't attempting to steal away the title of another game. The "4 Episode 1" distinction clearly says that this is the next game in that series. In terms of gameplay rules and visuals, Sonic 4 is a match. 3 act structure, boss at the end of each zone, 50 rings to get to the bonus stage, 100 for a free life, item boxes, badniks, checkerboards, etc.
Now in terms of physics, that's a different story. It IS different, as for how it functions varies from person to person. Some get so used to it that they find a very fun game underneath all of the differences. Others cannot get over it and to them it is a game breaker. I'm not calling either wrong, nor do I think we need to get into this debate. Nobody is "lying to themselves" in this regard. Those who are enjoying it, truly are enjoying it and those who are hating it truly are hating it.
The Episode 1 distinction is important, as it says that the game is not complete. Sonic Team and SEGA have a lot of room to expand and improve the game. If they want to create more fans for the full game, they're going to have to take a lot of the (level headed) comments to heart. As it stands now, Sonic 4 Episode 1 isn't a sequel "as I imagined it" as Sonic Team themselves have not even imagined it fully. I really do think that the complete Sonic 4 (Episodes 1-3) should be created via a dialogue with the fans, and thankfully that is how it looks to be going.
Remember "Sonic Fan Remix" when it was in it's infancy? It was actually not as loved as it is now. In fact, a lot of people had some very negative things to say about it. It wasn't until the past few months that the creator of that fan game implemented input from other fans and made it better. Now I personally did not enjoy the game, but I can absolutely see an improvement from the first screens to the current build.
With the above in mind, Sonic 4's process is a lot like this. The initial game had many problems: mine cart, pinball stage, rarely appearing wheel-o-feet, sudden stop at the end of a stage, no world map. After internal testing, and opinions expressed by fans over the leak, the game was much improved. Not improved to the point to please every fan, but it was still much improved. Now imagine Sonic Team taking what they hear about the final release of Episode 1 and implementing changes to make Episode 2 better: improved physics, an alternative to uncurling, new zones and enemies, Tails, etc. Right there, Sonic Team would be greatly improving Sonic 4.
So all-in-all, Sonic 4 could claim its place with the classics, but only once the game is released in full.