Actually it's funny you mentioned that you hoped Frank Oz would direct the Muppets again, not because it will happen (I seriously doubt that), but because the last time I watched MTM (oh, 2 weeks ago?) I noticed for the first time the drastically different humor and direction in that movie as compared to TMM or GMC, or the more current movies. For the first time in a Muppet movie there's not a lot of music softening the cuts... for example, think of the first scene in Pete's diner, when Kermit meets Jenny. It goes something like this: "My name's Kermit." "Hi Kermit, I'm Jenny." Cut to Kermit, close up: "I'm a frog." Hard cut to Miss Piggy watching Kermit and Jenny. Now IDK if it's because I majored in drama and my roommate's a film major that I notice little things like that, but it really different than previous Muppet humor ("Drinks on the house!" "What color are their hands now?").
TMM was always my favorite Muppet Movie, but I've found that for many people it's MTM, and when I was little that was my fav as well. It's just funny to see that now that I've, you know, kind of figured out for myself how the humor in MTM is different.
Watch it again (not like it's a chore) and let me know if you see what I mean!