I think the reason why the Muppets are so cool is because they aren't hip. They are ill fitting oddballs that just try to get it right.
I'm talking about the writing, of course. But it worked a lot better than the jaded and almost depressing Oz -which I STILL swear takes place in the world Kermit was never born. That dark, depressing, concrete mall and freaky night club had almost the same atmosphere as the ugly CGI Wizard and the horridly bright colors and the off kilter camera angles. UGH! It's a film that's not even pleasant to LOOK at.
VMX at least had a Muppety spirit behind it, though I could skip a bunch of scenes and watch the whole thing in 45 minutes or something and get a better flow. Again, I blame everything that stunk of the Simpsons writer's contribution... and NBC (they want promos of everything ON everything... even Forgetting Sarah Marshall, Get him to the Greek, and Despicable Me).
Anyway, any Muppety spirit was drained from MFS was do to the wonderfully brilliant director who thought Jon Arbuckle should be drained of any Jon Arbuckle spirit (that's going TOO FAR!). What do you expect when your masterpiece is the Chipmunks movie where they obsess over toaster waffles for no apparent reason?
Oh... and Oz was clearly going to be on Fox at some point. Why else would they have the obvious allegory to American Idol in the entire thing? They're almost as bad as NBC about promotions.