Which it sort of should, but mostly shouldn't.
It's actual levels are all fine. Running, jumping, smashing enemies open, it's all very Sonic. Classic Sonic, one might say. Let it be known at this point that I like Sonic, and I've played pretty much everything that Sega have churned out with his spiky blue face on the cover. Sure, most of them are utter guff, but that's besides the point.
I still don't understand why Sega feel a need to inject unnecessary peripheral garbage into the games. Sonic Rush had a nice balance, I thought. Enough story for Sega to congratulate themselves on creating something, but mostly just levels. Bosses were a bit of a bore, but you can't win them all and, thank god, at least it wasn't Sonic 360.
So, all well and good. Sega felt a need to create a sequel. First thing they did was add in another animal character for plot purposes. Nobody cares, Sega. Then they didn't get Hideki Naganuma to do the soundtrack, which is a shame. Then they put way too much focus on some drab stylus-based mini-game with a boat. Yawn.
I have to watch about ten minutes of cut-scenes before I can play some of the fun levels. Then I need to plot out routes with the stylus. I get why they're doing it; they're trying to justify the “Adventure” suffix they've slapped onto the game. Well, Sega, Phantom Hourglass has got that area covered. There's my adventure. I want some platform game, okay?
I feel a need to re-emphasise that the platforming part of Sonic Rush Adventure is great. But that's it.
Sega's problem with Sonic is that they fail to stick with one idea. Nintendo are very aware of Mario and, as such, games like New Super Mario Bros and Mario Galaxy are very polished, refined games that stick to the platforming. The Mario Party series has lots of mini-games. The RPG series caters for a more adventurous slant. Granted, we end up with a lot of Mario games, but at least they're not a confused mish-mash of wannabe genres like Sonic Rush Adventure.
(Keep in mind during the following comment that I don't actually know anything, and am speaking only on my uninformed suspicions.)
The problem is one of management. There are a bunch of guys who are good at platformers there, and they go off and do their thing. Then another programmer will say: "Hey! Wouldn't it be cool if we put this type of gameplay in?". And another programmer will say: "I just had the greatest idea for a story!". And a third will have a different game in mind, and a fourth will have a pet project he'd like to work in as a minigame. And so on, with the director on top not providing a vision but just figuring out how the parts should fit together. Everything they can think of goes in, and nothing gets left out. With each console generation the teams get bigger, and the bigger the team the bigger the mess this sort of development creates. The camera programmer sticks in cool angles which, while cool to look at, are totally disconnected from how the player will be controlling the game. The guy writing the script tries his sad best to write an epic, which distracts from the gameplay. Everyone involved in a Sonic game is genuinely trying to make it as good as it can be, but the guys on top aren't telling them not to do this, to focus on smaller details, to squeeze everything they'd personally like to do into a filter of what they're going to be told to do.
That is why Sonic the Hedgehog is a mess. And I don't see any reason for it to get better in the future, since team sizes are still growing.
Oh, and by the way: Nintendo could have the same problem. When you look at a Mario game or a Zelda game, you'll always see lots of different ideas from lots of different angles that clash with each other. What keeps this from getting out of hand is that Miyamoto's on top focusing them on a specific vision and steering them away from things that are too far off. If Miyamoto were to retire, I bet you wouldn't see such a difference between Nintendo and Sega anymore.
Looks like you should both take a look at the historic, genre busting Mario & Sonic at the Olympic Games for Wii. Now who's got mish-mash right? Has mory's prediction already come true?