Well, it's better than being off-topic am I rite?
I like your idea of bringing past stages as well, since Smash 4 may be the last game for a while, I think Sakurai and team should put all their effort into making it as perfect as possible, including the inclusion of past N64 stages.
This is
once again what Im hoping to see:
SSB64 Past Stages:
•Meta Stage
•Princess Peach's Castle Skyway
•Saffron City
SSB Melee:
•Brinstar
•Final Destination
•Fourside
•Battlefield
SSB Brawl:
•Lylat Cruise
•Norfair
•Castle Siege
•Bridge of Eldin
Those are a select few that I would really like to see if we didn't get all of them, I would be nice if we also got all the music related to those stages, more classic music would=better overall soundtrack IMO.