i think that anakin would have trained an aprentice after he killed palpatine than his aprentice would have become more powerful than him and killed him and so on and on and on.then the aprentice would have went 2 kill luke.eventually the droids would rise up against the dark side with a truce from the jedi and this would send the whole universe plumeting into war,disaster,hellfire,and death.
http://sp1.yt-thm-a02.yimg.com/image/25/m5/3264701157