What would be the advantage in trying to reinvent DJ?
Established user base.
Removes a "competitor" (not that they're adding users, but they still have legacy users).
Established resource forum (it's a turd right now, but a better hosting solution, updates, and some active moderators would solve that).
You could still completely rebuild the next version, stealing just enough of the original interface and feel, while having backwards compatibility. It certainly could be improved on.
No idea what it would cost to get the property, but it would have value that would give you a leg up on adoption.
At any rate, good luck. Maybe people will flock to a new map-app on the block more than I think... Stranger things have happened with Kickstarters.