I also think people give Kylo Ren too much credit when it comes to his saber skills.
Well, we were given evidence that he handled the saber with at least average Jedi ability.
1. He parried away laser shots from Rey while also advancing on her. And right before that, we were shown she was quite a good shot (and surprise, learned it by shot #2)
2. We are shown that the stormtroopers are trained in melee weapon combat (like Rey's staff). Despite that, he toyed with FN-2187. And he wasn't just overpowering him. Ren was clearly using some refined skill. Like Vader, it was so easy that he lost focus and started admiring his work too much.
I compare it to this
Campbell poses and Peden knocks him outLike Vader, he realized he needed to stop toying and actually fight to win, which ends the fight in devastating fashion in mere seconds.
As far as Rey's Plagueis stick talents, we watched her beat up two unarmed thugs and a cheap shot to Finn. Hardly proof that she is as talented ... with a non-saber no less.
it's not like Kylo Ren has met any major opponents in a 1v1 duel.
Despite the movie visual evidence, you could say the same about Darth Maul, Darth Tyrannus, etc until they actually fight. They had masters and it is accepted (and written about in novels) that they trained with those masters. Maul in particular couldn't reveal himself to the Jedi until the last days of his life. The Jedi weren't exactly fighting Sith in most of their life times. And yet, we seem them at their pinnacle of saber combat skills.
You could say the same about Vader. The Jedi were more or less gone and he was "rusty" when Luke came back. And yet he easily bested a half-trained Luke (as opposed to an untrained Rey).
The fact that he was severely injured combined with him underestimating both Finn and Rey resulted in him taking some bad hits.
He was toying with Finn. He was just admiring his work too much. I never saw it as Finn learned how to exploit a Ren combat weakness, but that Ren was having too much fun torturing the traitor. And I don't think he underestimated Rey at all. If anything, his character was written to fear her because for some unexplained reason, she was leveling up exponentially every 5 minutes. If anything, he wanted to stop her at 3:40pm, because she'd be better than Sidious by 3:45pm. He got thrown off because the sun disappeared and it went dark even though it was still 3:35pm. Perhaps the massive gravitational pull of that captured star was messing up his technique.
until they found Luke
I got the impression Snoke wasn't looking for Luke, but just making sure nobody else did. It was Ren that was looking for Luke. And I don't think we can even assume why. The easy answer is to kill him. Perhaps he either a) couldn't do it before because there was too much conflict in him or b) felt he wasn't strong enough, but now feels he is. Hux made it clear Snoke was about destroying the map, not saving it. So Ren couldn't say "I have the map, now power me up so I can kill Luke." That would be against Snoke's plan. Therefore, Ren felt he was powerful on his own at that point. And what better way to prove he was stronger than Vader by doing what he couldn't ... kill Luke. Assuming he wants to kill Luke. Maybe he wants Luke to bail him out. Han can't bail him out, so he had to pick the stronger side. But maybe Luke can. Maybe the double agent thing is right and it is time to get Luke to kill Snoke (hopefully not).
But being taken off guard by another force user, it became clear that Ren was far from the fully trained Sith that many people assumed he was when he entered the screen.
Sith? I argued on the Star Wars thread here he shouldn't be a Sith almost a year before the release (and was told I didn't know what I was talking about). JJ confirmed before the movie. We don't even know if Snoke is a Sith. And not *fully trained* doesn't mean you are severely lacking. Lennox Lewis was infinitely better in his 2nd reign than when McCall put him down. Wladimir Klitschko was infinitely more complete after Corrie Sanders laid him out. But "still getting better" Lewis and Klitschko would beat up a debut pro-boxer debut with no amateur fights.