I have to say that this film is definitely a top-tier Muppet movie. The movie was very much a nod to the classic vision of the Muppets, and I would highly recommend it to anyone who loves the Muppets. I ended up sitting through the whole movie grinning ear to ear, not only out of Nostalgia, but from the movie being just plain fun.
I was completely surprised at how much I enjoyed the musical numbers. They blended more serious or emotional song tone found often in early Muppets with a wacky/campy feel to keep it entertaining, and it really worked out well. I spent most of the Man or Muppet song laughing ---my bottom--- off.
I also thought it was very obvious how much they drew back to the "Classic Muppets" Many of the Muppets that had a major role in the later films, such as Rizzo and Pepe have been dialed back massively. At the same time, they gave much bigger roles to some Muppet throwbacks. The focus is on the Core Muppets. While I still do also like the Muppet work after Brian Henson took over (Muppet Treasure Island, Muppet Christmas Carol etc.), This movie has more of a Jim Henson flavor to it, which was great.
Overall, this was a great movie. This film saved the Muppet name for a new generation. It is so refreshing to see this after trash like Muppet Wizard of Oz.
The only sad thing is that Frank Oz and company aren't involved with this project. I thought it might have been due to age, but I checked imdb and they are still doing voices for other Henson/Muppet projects, so I dunno.
They did get Goelz but I think that is it. I read somewhere that Oz was not happy with the script but I have no idea if that is true. I honestly didn't notice he wasn't doing Miss Piggy but Fozzy was particularly bad. There were times when his voice would go in and out of character mid-sentence.
I also noticed that the voice of Fozzie was not that great at times, but the guy who did replace most of Frank Oz's Muppets did do an overall good job. I did also hear the "bad script" rumor, but at the same time had heard that he had unofficially retired from the Muppets (perhaps not sesame street) 10 years ago, and any additional work he did was only because he wanted to.