Actually, from what I heard, the last scene in the Batman movie DOES feature Harley Quinn, so I think that there COULD be an appearance. I think that she could be a good villain for him. Personally, I think that the Riddler could be just like the Joker was in this last one. I like the Catwoman as a "cougar" kind of character. Although, Brooke Shields or Cher, or maybe even Felicity Huffman might be good in that role. Maybe Poison Ivy can be another good character with Marsha Cross playing the role. I'd also like to see the Riddler played by Johnny Depp, considering that he creeped me out as Willy Wonka, if he could bring that kind of creepiness into it, then I'd say go for it. Although, if you're going to have a creepy Riddler, maybe Robin Williams, but then again, he'd be too cartoonish. I'd also try and make a new villain. Somebody that nobody's heard of before. Maybe make a movie for Batgirl. Reese Witherspoon, Drew Barrymore, or somebody could play Batgirl. But that's my thoughts on it, I'm not a comic book
geek ya know?
Daniel