Personally, I would like to see a movie set during Batman Beyond following the apparent death of Blight. It could be about Terry struggling with his dad’s death and finding a sense of purpose in his crusade for justice now that he has seemingly avenged his father. I think it could be a great character-focus, with Terry taking a hiatus as Batman for a few weeks/months. During this time, he keeps seeing clues that Blight may still be alive and causing trouble, inspiring him to don the cowl once again to stop him. However, he will discover that Blight is infact gone and that a villain (new or established) was behind the clues all along. Needless to say, this will convince Terry that he’s still needed as Batman and that his responsibility does not end when his need for vengeance is achieved. Obviously, this movie would be set between seasons one and two. I don’t feel like it would be a conflict of interest or anything, because I don’t believe it would step on the toes of the tie-in comic or any established storylines.
Second of all, I would love a New Batman Animated Adventures style movie where Mad Hatter and Scarecrow team up (The Time Sale/Jeff Loeb Batman Trilogy really proved how well they work together) or if it was Scarecrow, Mad Hatter, and Joker, or even just Joker and Scarecrow. I’d like to see Batman and Nightwing have to begrudgingly work together to stop them. Admittedly, I have not thought this idea very much out, but I think it would be a good concept to explore.
Thirdly, a Justice League Unlimited movie where they battle against the Secret Society (set during the show) that would use most of the original members (particularly Riddler and Scarecrow) mainly because they couldn’t be used at the time the show aired, and I would love to see a movie where the original LOD fights the Justice League (obviously, they wouldn’t be able to include Solomon Grundy, Brainiac, and maybe not even Grodd) but I think it would still be a good concept.