Fictional Fans

What is a book, movie, or series you WOULD like to see a sequel or prequel to? Or, if it's already had one of those, do you think it could be done better?

I got the feeling that Birds of Prey and the Fantabulous Emancipation of One Harley Quinn was designed on a platform of "come for Harley, stay for the Birds of Prey", and in the hope that if it did well they'd be able to follow it up with a movie that was just about the Birds of Prey without Harley upstaging them. I would actually like to see that movie: I think the Birds were all well cast and did interesting things with their characters, and bounced off each other well, and I'd like to see them work together for an entire movie instead of just the climactic action sequence. I'd also like to see Oracle show up in the sequel. (And as long as I'm dreaming, I'd like a pony.)

Speaking of team-up movies where the team spends the entire movie coming together and only actually works as a team for the climactic action sequence: I've seen it pointed out that despite all the movies Marvel has made with the Avengers in, they've never yet actually made a movie that's about the Avengers working as a team. The first one is all about putting the team together and they're a team for one action sequence and then the movie ends, and then the second one they're a team for one action sequence and then the team starts falling apart, and from there it's all been "putting the band back together" or "whoops, falling apart again". We've never had a movie that's just: here are the Avengers, they're a team, watch them solve the problem as a team, the end.