Extra Sauce
Member
That summary goes with what Natasha told me. I don't want to give away more of it because they're still using parts but the general idea seemed to be that Pen wanted there to be no one person writing it, that it would be written in chunks by the board artists. They looked at it when it was done and it was really disjointed, so they scrapped it and, as stated here, used the good bits for episodes in the current and next season. The plot DID sound pretty lame though, I was baffled that they couldn't come up with a more interesting story because it's fucking Adventure Time and they can literally do anything with the characters.
If you ask me, that sounds like a nearly surefire way to write a bad movie. It's one thing to bounce ideas off each other in a room but this sounds like they each wrote their own chapter in a corner, then Frankensteined all the pieces together.
So crazy it just might work kinda thing, maybe? Whatever the method, I do hope they try again in the future. An Adventure Time movie is simply something that needs to exist in my life. The potential is ridiculously great.