Fox wants a sequel but it doesn't look like one will be made soon, the Simpsons writers and producers have their reasons. But I think they real reason is they can't come up with a good enough idea to fill 90 minutes without it seeming like three long episodes. Despite what producers say, some episodes have a cinematic feel like "Raging Abe Simpson and His Grumbling Grandson in "The Curse of the Flying Hellfish"" and many others. One of the biggest complaints of the Simpsons movie is that we didn't see enough of the townspeople. My problem with it was its use of too much music over the jokes in the beginning, making them hard to hear. It reminded me too much of the scoring in The Goofy Movie and Rugrats Movie. "At Long Last Leave" reminded many fans of the movie itself as the Simpsons were kicked out of town.
I would personally like a movie that tied the characters together. I would like to see some of my favorite Simpsons writers like Bill Oakley, Josh Weinstein, John Swartzwelder (he wrote some for the first movie), and Ian Maxtone-Graham (he wrote some of the movie too). I would like some conspiracy within the town that would someone link the military (Principal Skinner, Abe Simpsons, etc.), the criminals (Snake, Fat Tony and the mob), and M. Burns (Waylon Smithers' dad was killed in a nuclear accident in a flashback in season 13). I was thinking of re-hashing the Stonecutters from season 6 and Maggie's position as the 'gem child' in "Gone Maggie Gone" from season 12.
In "Gone Maggie Gone," Nuns took Maggie on a throne, causing a light to hit her which makes a rainbow that brings peace all over Springfield. Marge took her back. But maybe the nuns can come back to get her back as some apocalypse might be happening. Apocalypses and conspiracies are not new to the Simpsons but if it has enough of the lore from the past 26 years, it could be something interesting. Maybe Selma B. is dating Snake and Snake has been hired by the Mob with a big secret. But of course this seems like a lot of elements from the 90's and not enough from current but it can derive from a combo of all. Like for example, in recent years Edna Krabpel married Ned Flanders and later died because her actress Marcia Wallace died.
Related: http://spanengrish.blogspot.com/2008/09/simpsons-sequel-circles.html | http://www.cinemablend.com/new/Fox-Wants-Simpsons-Movie-Sequel-Here-Latest-67575.html