I think it is safe to say that everyone who saw Star Wars Episode VII: The Force Awakens, whether they liked it or not, freaked out when Kylo Ren stopped a blaster bolt in midair. Sure, we've seen some cool uses of the Force before, but this...this was an inventive way to employ a power that we all thought we had seen done every way it could have been done. Couple this with Kylo's impressive ability to pull information out of people's heads and it would seem that Ren is one of the more powerful, if not the most powerful, Force-wielders we've ever seen in a Star Wars film.
But, as many, many, many, many people all over the Internet have pointed out, Kylo Ren was not the best with a lightsaber. He seemed sloppy and untrained in comparison to his skill with the Force. I think there are a few logical explanations for this and I think as the movies continue to be released, we'll better understand these reasons.
Luke Skywalker Didn't Train His Students To Use Lightsabers
I think that a broken Luke Skywalker emerged from the second Death Star in Return of the Jedi. He had helped defeat the Empire, his friends were saved, and he got to party with Ewoks. Yay!
But I think that the troubled young Jedi had very little faith in himself after the Battle of Endor. He had been saved by his father's return to the light side, not his skills with a saber or the Force. With no one left to duel, I believe that Luke began to focus on strengthening his abilities with the Force.
If this is true, it would only make sense that he would focus on that while teaching his students as well. I think that Luke was very hesitant, if not outright unwilling, to train any of his students, even his nephew, with a lightsaber.
This might have seemed to be the more peaceful and smart decision at the time, but I think that in doing this, Ren formed some sort of resentment towards his uncle and pushed him into the welcoming arms of Supreme Leader Snoke.
It is under Snoke's guidance that I believe Kylo Ren constructed his lightsaber and returned to his uncle's temple to kill the other students. With his natural ability to control the Force and now armed with a lightsaber, Kylo Ren waited until Luke was away and murdered all of his peers, with the exception of those who followed him to the Dark Side (notice how none of the Knights of Ren have lightsabers)?
Kylo Ren Was Trained To Use The Force From Birth
This is a simple matter of luck. Anakin Skywalker, as powerful as he was, didn't begin his training in the Force until he was almost a teenager. Luke Skywalker began even later with very little guidance apart from his short stints under Ben Kenobi and Yoda. Kylo Ren, however, has the raw strength in the Force that his uncle and grandfather had and has had the luxury of being under the constant tutelage of someone strong in the Force since his birth—first, Luke Skywalker and then after that, Supreme Leader Snoke.
While many of us look at Kylo Ren and see someone in their early 20's, I believe that he's closer to age of the actor, Adam Driver (32,) who portrays him. This means that Kylo Ren has been training in the Force for at least 25 years, possibly more.
So What Does All This Mean?
I think that in the upcoming Star Wars Episode VIII, we'll see Kylo Ren go through some serious lightsaber training. With new enemies to fight (that sometimes wield lightsabers) and in the face of his defeat on Starkiller base, Ren will throw all of his focus towards his physical combat abilities. I also think that we will see flashbacks, or perhaps just explanations, of the events I described above.