I think it'd be awesome if you completed all of the side-quests and beat ganondoft, then it would let you continue after ganondorf was defeated, go to ordon, see everyone together again and happy, etc...
THEN more side-quests would open up allowing you to do even more! Plus giving you a reason to get everything in the game before you beat it. Then you could get a few cool items, stuff that would let you have fun in Hyrule after it was saved... like, a skateboard! lol, jk jk, even though that'd be cool. I dunno, like a flying horse to glide around and see hyrule at a different angle, or unlock a new area, oor a tunic that allows you too breakdance, I dunno man, just shooting ideas out! I think you get the point.