I had to have this conversation with a co worker because like some I have seen online he just doesn't get it.
This is the start of his story on screen. He is so use to seeing a Maul/Vader/Sidious/Dooku show up on the screen already trained to their full potential. Kylo Ren is still raw. Which is why Snoke says to retrieve him so they can finish his training. We will probably see him get more powerful in the films as opposed to previous villains that are what they are from the beginning. This is obviously part of what Kasdan meant by him being unlike any villain that has been in Star Wars. We haven't seen a Villain develop along with the hero before in a Star Wars movie. Also he will probably have a different lightsaber in episode 8.