The final lightsaber duel(s) in The Force Awakens divided a lot of fans. On the one hand, it was something much more raw and frightening than the lightsaber duels of the past: way different than the stiff, barely-making-contact duels of the Original Trilogy and the balletic, too-well-coordinated duels of the Prequel Trilogy. This was two completely untrained individuals (Finn and Rey) going up against a semi-trained (but enraged and injured) dude - and shot in a way where you actually felt each impact of the lightsabers against one another.
What made it divisive, however, was the fact that Kylo Ren - who was trained for YEARS under Luke Skywalker and Supreme Leader Snoke (not at the same time, obvs) - could barely handle Finn OR Rey, two complete novices.
...or IS that the case? Youtuber Derek Miller posits that - especially with Finn - Kylo was merely toying with his prey...and in the exact same way Vader toyed with Luke (instead of going straight for the kill) in Empire Strikes Back:
Can't wait til they reveal Kylo Ren was actually Finn's dad the whole time. Finally, some validation for my fan theory.