Disney really just needs to give the Muppets a little more breathing-room and allow them to mess around a little more. They were too focus-grouped, too on-script and too careful the last film. The kind of had to be for the relaunch, but that's over now so they can all loosen up. That sort of spontaneity is really the only important component missing under Disney ownership. Otherwise, I think they've done right by the Muppets.
My complaint is with the stop and go they have with Muppet promotion. Well before the movie they had a huge momentum of Muppet stuff. The XD website, the Youtube videos, the comic books... then a dead stop until the movie, when everything was focused the movie promotion, then a dead stop immediately after the film was done in theaters, then a small uptick when the film came out on DVD, and then another dead stop.
Now I understand they're being strategic, and trying very hard not to over expose the franchise, but it seems they're walking a thin line of strategic and overly cautious, when they needn't be. The thing that completely gets me is the lack of Muppet Merchandise in Disney stores, considering that the plush dolls did gangbusters last year. Things have dramatically improved outside of that, though... but there needs to be a bigger Muppet footprint in stores by the time the second film hits. I do have a 90% approval rating of their handling, though. Henson wouldn't have even got so much as a DTV/telefilm off the ground.
Other than that, there's no excuse for not making another viral video since the movie trailers.