Futuristic magical girls? I like that. A future Tokyo where technology is now part of the city itself and magic now seems even less plausible than ever. I dig it.
As for the "weekly bad guy fights", for a written roleplay... yeah, it definately doesn't seem like a good idea. We would have to follow a very strict structure. We need something different. Maybe just fighting a criminal group that uses magic as a means to control the city? Like, wizard-yakuza or something like that...