Oh come on man, you are gonna take EU Luke and put him in a movie? The history channel is already doing that. Its called "The Bible" with EU Luke Skywalker playing as GOD.
Who even knows, this is Luke at his fullest potential realized? Who knows, that he'll be a main character anyway? Besides, a Mary/Gary Sue/Stu isn't just a person who has insane power, they also don't have any flaws, they have things go there way, their life is perfect etc etc. Luke aside from his insane power(which he gained over time, it isn't like he woke up one day and was like that so even then that doesn't make him a Sue cause he worked on it), he isn't a perfect being.