So far I've just been lurking, watching the old school and the new school duke it out, but I'm going to give in and throw in my two cents.
I have played these games, and I enjoyed them in their day, but I think that in order to make Double Dragon (or any beat em up) successful today, developesr will have to consider how to improve the genre. I'm sure there are still plenty of players who love old school fighters like these, but I don't think the bulk of modern gamers will accept them in their classic form.
Case in point: a game with no save feature is pretty much unheard of nowdays, but the Double Dragon series would have been way too easy if a save feature was included. I don't think the game will be received well if players can't save, but how do you keep the game from being too short without getting boring and repetitive if you do allow them to save?
Anyway, I'm not against the idea, not at all, but I don't think it will be really successful unless the developer does it "right".