I'm of the school of thought that we should have gotten a Simpsons movie in 1993, helmed by the Season 4 writing staff like they'd heavily considered at the time. If we'd channeled the writing prowess of the show's finest creative team at the height of the show's quality, that could have been among the greatest comedy films ever made - and released around the peak of the show's popularity, too.
A second Simpsons movie will either be really mediocre or really excellent, depending on who is creatively responsible for it. The original Simpsons Movie in 2007 was written by a team consisting of writers from the show's Golden Age, roughly the first seven or eight seasons. Not only did you have the original triad of Matt Groening, Al Jean and James L. Brooks, you had your John Shwartzwelder (veteran writer of 52 episodes), your George Meyer, your David Mirken, your Jon Vitti, all the greats who penned much of the show's classic era. All things considered it came out surprising good compared to the state of the actual series by that point, though none of these people actually wrote for the show any more except for the odd script.
You had the movie coming out right before you got to season 19, which is when the recovery period of Season 13-18 was back to a full decline in quality. Whereas Season 11 and 12 had to succumbed to trying to compete with the wackiness of Family Guy and gone off a deep end when it came to storytelling - and Al Jean made a very good decision to try to dial that back and return the show to its roots in Season 13 - once you get past Season 18 you really get to another point where there's fewer enjoyable episode than there really mediocre ones. Especially by Season 20, which if you ask me the consistently the weakest season of the show and the last one I followed consistently - and this was a decade ago when I was a woman of less discriminatin' taste.
Having over the years eventually gotten around to watching through the post-20 seasons, I've at least located the rare gems I can go back to. It's really really sad when you have two episodes as good as Season 23's "The Book Job" or "How I Wet Your Mother" and they're the outliers in the same season as "Lisa Goes Gaga" (contender for the worst episode ever) and "Them, Robot" (which was not only unfunny, but they brought on the wonderful Brent Spiner as guest star and didn't even give him any good material).
And I don't think I've rewatched anything as much as classic Simpsons episodes, so me not feeling an episode is rewatchable whatsoever is a pretty grave condemnation. This show was once the greatest comedy show ever made and now it's just mediocre...and yet it's still way above average compared to most popular sitcoms.
Anyway, here's hoping they can get the gang back together for another good movie, because at this point a worthy successor to the first film feels like the only way I'm ever going to get more new Simpsons I can say I actually love.