Do you think she'll turn to the darkside later?

Yea, why not; I'd even be slightly surprised if they don't use him before X. Because, stuff.

One thing I'm still wondering. What did Vader start that Kylo wants to finish? The extinction of the jedi? Bringing order to the galaxy? Balance to the force? He never explains it and neither do people who say that same phrase as if it explains his motivations.

He started playing GTA III on PS2 but he never finished. Game was fun but Anakin spent all of his time goofing off and never finished story mode.

That's my guess, anyway.

You'd have to make Kylo less of an amateur for that to work.

With what we got from The Force Awakens, Snoke would be more fit to summon Anakins spirit, like being so powerful and in control of the Darkside of the Force that he can manifest Anakin back, perhaps at the same time he torments him.

No. This time the Force will do it right.

and BB8 has the only copy left in the galaxy

"how did he jeopardize Luke's brining up of a new generation of jedi?" is that something a character said in the film? I can't remember. Was it Lor San Tekka by any chance?

Maybe his alliance to the Darkside of the Force jeopardizes the Jedi, but the biggest menace right now appears to be Snoke.

I think they are trying to build Kylo alongside Rey, like having them going through training and have their final showdown where Luke and Snoke's apprentices will show what each taught their pupils.

I bet that in next film they will make Kylo very powerful doing some incredible feats and antagonizing stuff while making Rey feel like she needs to do some catching up, strengthening Kylo's image and turning him into an ultimate villain while allowing Rey's character to have a real aim of becoming better and more powerful.

I like character development, so I like the idea above. I was just a little disappointed at how they portrayed Kylo by showing him as a very powerful Sith and losing that image gradually as the film progressed. The lack of Force use during the final battle was noticeable as well.

A what to be reckoned with?

I went back to the film and looked for that part and Han Solo talks about Luke disappearing because he trained a new generation of Jedi but a young apprentice betrayed him and "destroyed all" and Luke felt responsible so he decided to abandon everything.

The question here would be what Han meant with "destroying all". It is possible that refers to destroying the confidence and dynamic Luke had in training Padawans making him going reclusive.

I am not sure that young apprentice is Kylo Ren. It could be Snoke. Maybe the key to finding this out is to go back and check how many years Luke has spent reclusive and compare that to Kylo's age. I don't remember if that info is there in the film though.

I completely get what you mean. I also expected a badass Sith in Kylo Ren but felt we didn't get it. Now I look at his cool costume and image and say to myself that I would put his picture in my desktop background but then can't because I feel his sort of a wussy.

Like I wrote above I feel the writers opted instead to have in Kylo a villain-in-process, so I have to wait and see what they do with him but he wasn't what I expected, definitely. He was what I expected in the beginning of the film, then became something else.

Remember though, there is a difference of power in the Force and Lightsaber skills. Maybe Kylo is very strong in his power of the Force, but not very skilled as a Lightsaber fighter, yet.

The "frustration" or feeling of "betrayal" that Luke may have felt with whatever young apprentice went rogue may not be the result of Luke being overshadowed by the apprentice's power of the Force or skills, but of the disappointment of having someone he cared for turning away from him into the Darkside.