I personally would have liked Kylo Ren be a more threat to Rey, not because I want her to be put down or a Vader rehash, I just really like dire moments and villains that push the protagonists to their limit. I know Ren is basically padawan level, and I actually did like that his mind tricks were not up to par against Rey (even a non-force sensitive can actually beat the mind trick, people who used to assassinate jedi through subterfuge would have various ways to cloud or overcome the implanted suggestions), but also being on the losing end in the physical aspect of a lightsaber battle made him seem overall a weak dark apprentice. Him not pulling the lightsaber instantly and having Rey overpower it seemed weird when he is capable of stopping blaster shots and pulling a grown man into a choke hold. Now, I know someone's going to mention the bowcaster shot from Chewie, I knew when he got hit, that would play a role in the battle when I saw that. His wound plus the emotions he was feeling after killing Han were probably doing a number on his physical and force prowess, but it feels like one of those story points where a lot of caveats have to line up to make a 1v1 viable. I personally just don't like fights with too many caveats in a lot of fiction, in the end results still happen and he is holding that L.
I also like him punching his wound to basically amp himself through the pain. Even though the EU is dead, one Sith that I really liked from KOTOR 2 is Darth Sion, because Sith can attain a level to fight through pain, and Vader has that aspect to him as well being pretty much 90% cybernetic after Episode 3. If he fought through the pain and showed he had the upper hand in the fight, I would be thinking, "Damn, maybe he is good at this Sith thing." but he didn't, so we know that he doesn't have that "terminator" aspect that really strong Sith have.
I think he and Trashma are going to have to work overtime to win back their cred, which is much harder than starting out badass and dying a punk, like Boba Fett.