SilverWook said:
Time travel has never been part of the SW universe, (not sure about the EU) except for Luke's line to Threepio, and that was probably a joke.
Time travel's shown up a few times in the EU.
http://starwars.wikia.com/wiki/Time_travel
While I don't mind the idea of time travel occurring in the SW Universe -- and certainly wouldn't mind seeing it explored in one of the spinoff films -- I don't think it should be featured in the ST itself.