From what we've heard, the film doesn't sound like a typical-Segal movie. He wrote it with people like us in mind. Just give it a chance.
Indeed. Anyone thinking it will be exactly like his other movies (which, really? is that a bad thing? They're more brilliant than any other adult comedy and the romantic bits are a million times more organic than half the chick flick garbage out there), is out of their minds. Sure, you can see unique brands of his humor here and there (mainly the 1980's references), but other than one fart joke... and not even a real one, I just don't see a problem. And let's not forget... if not for Segal we wouldn't even have a Muppet movie at all... and even if we did, they'd probably have hired Simpsons writers again, making 100 dated pop culture references per second. Much as I love VMX, most of the jokes were unnecessary (did we need the Crock hunter and the refernces to poorly dubbed Kung Fu movies at the end?) and very much a product of their times.
Which brings me to humor... well, we all have to realize that humor evolves over time. And we'd better be thankful they have, or we'd still laugh at cheap stereotypes of Asians (You don't know how many 1960's cartoons thought they were being funny by adding random pigeon talking characters that needn't be there. Even in some of my favorite shows, like Mighty Heroes). They aren't funny by any stretch, except for ironic reasons, and just make me feel uncomfortable. It took me forever to get new humor... but I was greatly rewarded when I did. Not that I don't like the classic stuff too (in cases of the timeless stuff and certain things that can't be replicated).
As far as a Muppet movie goes, I never think we'll ever get back to the level of the first three. That's like expecting Taz-Mania to be exactly like classic LT shorts (though, frankly, I think modern Taz was a huge step up from the original and Jim did a better job than even Mel did). I just want something higher quality than Oz. A Muppet movie would have to be pretty rank to be worse than Oz for me to not recommend it. Other than the fact I've still yet to see Swamp Years, I've enjoyed most modern Muppet projects. Worst case scenario, the movie is enjoyable C+ type stuff...