Now that I have had all weekend to process the awesomeness of the trailer, I can properly comment on it.
One of the first things I noticed was Rian Johnson’s little nod to Looper where Rey causes the stones to rise up off the ground. It was very reminiscent of his early time-travel movie. Also, they seem to be trying to throw people off with the scene of some cloaked figure watching a building burn while kneeling next to R2. Before that we see Captain Phasma and her goons destroying a base and walking through fire & wreckage, then we see that scene. It would almost seem to be the same area, but just from a different angle. However, if you notice, Phasma looks to be in a hanger, the ground is solid, etc. Whereas the burning building looks to be on dirt. So my guess this is a flashback of Luke watching his Jedi Academy burn to the ground.
My other big takeaway is still the title and Luke’s final words: “It’s time for the Jedi to end.” My guess is that during Luke’s seclusion with his minimalist Jedi library, he has discovered a basic truth about the Force (the light & dark aspects are not good/evil). I have said multiple times that the Force knowing good from evil is weird. What if you channel anger and use that to save a bunch of kids? Or what if you are a sociopath and can easily slaughter large groups of people without a hint of negative emotion? Seems a little odd right? Maybe that is what Luke is trying to teach Rey, that you can harness either side of the Force, that it is the person who chooses what to do with that power. Maybe she will become something greater.