Thing is, George allready wrote so many books that Disney just threw away when they bought the franchise. If there had been no books, then Disney could have done what they wanted. But what they did, was to change everything about an allready existing universe. In the books, Luke was the most powerfull Jedi that have ever lived, mastered several lightsaber techniques and was able to battle against an entity of pure force just to mention a few. In the movies, he just, dies.. Here is a quote of some of his feats from the books that existed before Disney..
-"As the Grandmaster of the New Jedi Order and the Jedi Coalition, Luke spent most of his teenage and adult life honing his force powers and combat ability to perfection. Over the course of his life during the EU, he demonstrated the ability to tap into multiple force powers such as Electric Judgement, mnemetherapy, telekinesis and telepathy. In combat, Luke has demonstrated the ability to react within nanoseconds and fight FTE while Jedi Knights such as Leia and Jaina (who can react to above hypersonic speeds) are watching"-