Let me start by saying, while I am a fan of Star Wars, I am by no means an expert. So if I cross any canonical lines, as far as the novels go feel free to correct me down in the comment section.
The design of the character Kylo Ren strikes me as someone from the Crusades. The cross-bladed hilt on his light saber also strikes me as a weapon from that erea. A kind of over-the-top activist that takes his perception of his idol's beliefs to the extreme. Always seeking a kind of approval, but never getting it (bc Darth Vader is dead). I feel like we will see some mimicking of Vader's behavior in this first film from Kylo as well. We saw what happened to someone that questioned Vader's command in "A New Hope", I hate to see what happenes to someone that questions Kylo Ren.
The other thing that i noticed during the final trailer is the settings. It appears to me (and it may only be me) that the small glimpse we see of Luke SKywalkers hand petting R2-D2 isthe same setting as when Kylo is seen ravaging a village/area.
If Kylo Ren is there to finish his idol's work and hunt down the last of the Jedi, maybe he finds Luke early in the movie. Maybe he ends Luke's existence in Act 1 of the film which is teh event that "Awakens" the force. This is what could possibly cause Finn to feel the force hit him so hard. What makes Rey wake up to realize who she really is. All while being guided by the Jedi ghost of Luke Skywalker.
As seen below, Kylo Ren is striking down someone at the camp where he and his storm troopers arrived. My guess, it's Luke.
This would also take Kylo's character from 0-60 as far as depicting how brutal he really is. Not to be taken as just a copy-cat Sith wannabe. Killing Luke can also be the awakening of the Dark Side for Kylo. It has been stated that The Knights of Ren are not Sith. Maybe that's because they could not harness the force before this event? This would also explain how Kylo seems to motion as if to be using the force already. It would also solve the perplexion of some fans as to how Finn and Kylo can weild a light saber so quickly, as most Jedi need to be Force proficient to not lop off any limbs.
Just a few things that stood out to me, again, not a hardcore fan. So if i am wrong anywhere in my thoughts/theories feel free to fill me in, I'm still learning too.