Having a bad guy turn into a good guy is the laziest and the least interesting way to explore moral ambiguity. You can have moral grey areas and humanized villains without ignoring the fact that they are villains.
A good example of this? Darth Maul from Clone Wars and Rebels. He had loved ones, a tragic story, and sympathetic moments but they never lost sight of the fact that he was a villain and he brought about his own downfall.
I hope Kylo Ren gets a tragic end similar to Maul’s. It would be a lot more interesting than just making him a rehash of Vader.
Also, “Fascists are people too” really is not the story we need in 2017.