All right, before getting into the nitty gritty, I'll suggest that there's only so much obsessing to be done over details, plot, music and character screen time before we step back and recognize that no matter what happens with any of these things...
WE'RE GETTING ANOTHER MUPPET MOVIE, POSSIBLY LESS THAN TWO YEARS AFTER THE MOST RECENT ONE HIT THEATRES. There's absolutely nothing about that statement that isn't good news and doesn't make me smile.
Now, on to the questions:
1. What would you like to see as the plot in the new Muppet "comedy caper" type film?
I'm not particularly worried about the plot, as long as it achieves the stated goals of (a) concentrating on the comedy and (b) incorporating the classic Muppet characters. I don't think it has to be rooted in the Muppet Theatre (as per The Muppets) but I won't mind if there's some "connective tissue" to the most recent film as Stoller described. That being said, I really don't want an outright sequel and will be disappointed if it's marketed in that fashion.
2. What characters would you like to see have the leading roles?
I'd like to see "take-charge Kermit" back, now that he's dealt with the various issues that arose in The Muppets. More screen time for Rowlf, Statler and Waldorf, Rizzo and Pepe, please. And, of course, the usual suspects: Piggy, Fozzie, Gonzo, Scooter, Sam the Eagle, Bunsen & Beaker, Sweetums, the Swedish Chef and the Electric Mayhem (there MUST be at least ONE killer Mayhem song in this movie, as has been previously suggested).
3.Do you want a Muppet villain (like in Muppets From Space, Letters to Santa and The Muppets) and if so who, or would you prefer the villain to be just a human role for one or more characters?
I think it would offer more variety to the film, and to the Muppet canon as a whole, if the idea of a single villain was discarded in favour of numerous obstacles that the Muppets must overcome to achieve their goal (whatever that might be).
4. Whether they were in The Muppets or not, what five minor characters do you hope have a bigger role in the new movie?
The definition of "minor characters" is open to discussion but my votes go to Link Hogthrob, Dr. Julius Strangepork, Lew Zealand, Robin the Frog, and the duo of Johnny Fiama and Sal the Monkey. (I wouldn't mind Bobo sitting this one out or stepping back...he got significant screen time and some great lines in Muppets From Space and The Muppets, so let's spread the exposure around a bit more.)
5. What style of music would you like for the new film? Are there any characters that you hope have a song in the new movie?
As I've mentioned above, I'd love to see at least one big crazy Electric Mayhem number and, whether or not the flick follows the "Muppet road trip" theme mentioned by others, I'd love to see another great road-trip type of song like "Movin' Right Along."
Bottom line: LET THE MUPPETS SING! They didn't actually get to do a lot of that in the last movie (for new songs, anyway) and I hope that changes with this one.
Finally - I'd be delighted to have Walter back (I thought he delivered some of the biggest laughs in the previous film) and I'm not worried about new Muppets being introduced. As others have already noted, new characters didn't derail MTM or MTI and I'm sure they'd take their proper place in this new movie.