[Star Wars: Episode VII — The Force Awakens](tag:711158) was an overwhelming success that, while not completely surprising, caught a lot of people off-guard with its box office numbers. The film grossed $2.066 billion worldwide, becoming the third highest-grossing film of all time. Audiences responded well to the story and the highest points for many fans came in the form of the franchise's newcomers - specifically John Boyega as Finn, Daisy Ridley as Rey, and Adam Driver's Kylo Ren, son of Han Solo and Leia Organa/Skywalker. The young dark side enthusiast was incredibly insecure and constantly struggled to stay on his self-chosen path, which led to lots of fans hoping for the character's turn to the light side in Episodes VIII and IX of the planned new trilogy, much like Darth Vader in 'Return of the Jedi'. However, I believe that Kylo Ren must stay true to the dark side if the story is going to be satisfying.
Why Kylo Ren Must Remain on the Dark Side
Kylo Ren's biggest trademark is how far he is willing to go and what he's willing to do to prove that he is a worthy dark side apprentice, due to the doubt that shrouds him to turn back to the light side. One of the biggest examples is his "ash tray".
This thing is in his interrogation room, and is a collection of ash from his dead enemies. This is extremely dark, which is most likely why the detail wasn't revealed during the PG-13 film and had to be explained by the director afterward. It begs the question, is Kylo Ren redeemable?
I see Kylo Ren like an underage boy who is surrounded by friends who smoke and drink: It's not at all his style, but he'll do anything they do because he wants them to accept him. At the very beginning of the film, Kylo murders an elderly man who he previously knew; the details of their bond are not very clear, but it's easy to assume the villain knew him from his childhood.
Leia stated in TFA that Supreme Leader Snoke seduced their son, previously known as Ben, to the dark side. So, Snoke is someone Ren admires and wants to be accepted by, but during the film, we see how Kylo is almost begging himself to remain on the dark side despite his instincts.
That means he is doing all of these horrible things to convince himself that he belongs in the darkness. He needs to constantly remind himself of that fact. We get the biggest proof of the doubt plaguing him in the horrible act he commits: Murdering Han Solo, his father, who was letting him know he was not alone in his struggle.
Some will argue that Darth Vader did even worse things by murdering children and making Alderaan, a fully populated planet, go boom. But here's the thing: Darth Vader was good as a young man. He lost his mother in a horrific way, he was in love with his wife and crazy for being a father. He was one of the most powerful and noble Jedi in the galaxy. What turned him to the dark side was his fear of losing everything he held dear. He didn't want to live up to a legacy, he didn't want to fit in, he didn't want power for the sake of power, he wanted it to save his wife.
Some will argue that Kylo Ren was good too and found himself in the same dilemma as Vader but that's most likely not the case; why? From what we can gather from the movie, he was living a good life with his parents, who both love him very much, until Snoke came up and took him away. What made him turn? His pride? He wanted Snoke to like him? To be more powerful? Was he a moody teen? As far as we can tell, he was not in the same desperate position as Anakin Skywalker when he made his turn to the dark side.
To strengthen this point, take a look at this interview where Adam Driver describes the character (Specifically at the 00:47 mark):
"(Ren's lightsaber) is such a big metaphor for the character, you get this sense that at any moment it could not work and spontaneously combust. I think it says a lot about who that person was."
Having said this, he's been committing all these atrocities, most likely out of a twisted sense of pride. And while he's shown to be conflicted in 'The Force Awakens', his desire is to remain on the dark side. For this reason, redeeming him in Episodes VIII or IX would be extremely unsatisfying. It wouldn't give you that sense of fulfillment you had when Darth Vader decided to come back to the light side to save his son because this is a ruthless guy who already murdered his father to prove to himself that he was edgy. His problem is insecurity, which could make (in my opinion as an audience member) the fact that he is a hero very uncomfortable for the story.
Kylo Ren works well as a ruthless Star Wars villain. He is insecure, brutal, a killing machine; overall, a worthy adversary for current and future heroes in the franchise. Redeeming him would be a way for people to not hate him completely, which is not good for a BAD guy, specially in Star Wars, in which we've had a LOT of morally-conflicted antagonists. That isn't to say that he couldn't work with the story's real heroes within the next two installments. Realizing Supreme Leader Snoke's true intentions toward him might force an uneasy alliance with the Rebels to take him down - which would be a much cooler story.