To get back on topic for a moment, the three villains I would like to see in the next batflick are riddler, bane, and catwoman.
Riddler-FBI profiler sent in to aid the gotham police in apprehending batman. He becomes obsessed with him, reading everything documented on the vigilante he can find. Nigma goes so far as to stage crimes in order to see the batman in action. I could see him initially not wanting to hurt anyone, but when one of these incidents goes wrong and several people are killed the police begin looking for the one responsible. He initially tries to pin it on batman himself but gordon and batman have been communicating and he knows nigma is lying almost as soon as he brings it up. Knowing it is only a matter of time before gotham police close in on him, he creates the alias of the riddler to keep the gpd off his tail. Now that the police have a name to go after they slack up a little on nigma. He is still obsessed with finding batman and stages several more accidents still trying to bring down the batman, maybe even have him make an appearance in costume at this point. Batman and Riddler would be a complete battle of wits, in the end. I see him as the joker character in the next one. Becoming completely obsessed with batman.
Bane-Bane I see more of as a scarecrow like scene for this movie, go into his background a little, make it clear he is smart but not on the same level that batman and nigma are. I would like to see him have ties with ras al ghuls league of shadows, maybe have him taken control of whats left of the league members still in gotham, He is less obsessed with destroying gotham and more obsessed with destroying bruce wayne, he would target only wayne enterprises through his league. His leadership skills leave something to be desired and its his lack of leadership which lead to his ultimate defeat and capture by batman.
Catwoman- selina kyle I see more as the harvey dent of this movie, and I only say that because she goes after one particular group, those she feels have wronged her. Her character I think should stick with the prostitute angle from frank millers year one. I would like to see her get into a relationship with a falcone, either alberto or mario two of carmines sons, that now that their father is out they are having to work their way up from the bottom. Whichever one she gets involved with finds out about her job as a prostitute and breaks it off, fearing what it will do with his standing with the family him being in a relationship with a hooker. Angry about what has happened she would adopt the catwoman persona to go after these people, her pimp, the falcone brothers, I could see her killing the pimp, and maybe trying to go after the brother she wasnt dating, leaving him with the scar she left on carmine falcone in year one. She would run into him while robbing the safe in their safehouse. She would eventually go after more high profile targets which set her in batmans sites.
just some ideas