No one here is saying it's perfect, SpaceMuppet old bean. It's just really, really good - probably even great, in my opinion. The best part is that it opens the door for new Muppet projects, so for that, pretty much everyone is grateful.
Here's one thing that did bother me: The Songs. (WHAT?!) Yes. Not that they weren't well written and well sung/danced, but it's that... they weren't Muppet songs.
Bear with me. (Pun.)
The Muppet Movie had "Rainbow Connection," "I'm Going to Go Back There Some Day." "Never Before, Never Again," and "Can You Picture That." (I'm leaving out "I Hope That Something Better Comes Along, for the reason mentioned below.)
The thing with Muppet songs is that they could be sung by anyone, anywhere. They don't need to be within the confines of one plot or one character. And they're powerful. They tackle all kinds of issues, beyond the realms of Muppets and Puppets. Or, they're fun, and work as stand-alone tracks (Picture That, Never Before.) In fact, I can't think of an occasion where the Muppets refer to themselves as Muppets in songs (I could be wrong.)
The new songs in THE MUPPETS don't work that way. Sure, "Pictures in My Head" is emotional, but no one but Kermit the Frog can sing it for it to still make sense. And it only touches Muppet fans. "I'm Going To Go Back There Someday," "Rainbow Connection," "When the River Meets the Sea," and so on, are all amazing because they speak to human conditions and simple philosophy. (Not to be all cheesy - I'm not saying they're super deep, but they have depth.) The songs in THE MUPPETS are very one layered.
That's my only major complaint.