The newly-released teaser trailer for Star Wars: Episode IX was indeed simply a teaser. Two minutes is a decent length, but it was careful to not show much of anything--which frankly made it somewhat boring to me. But of course, anything that they do show gives us the chance to guess and surmise and theorize. So let's commence with my thoughts on all that (not having seen anyone else's thoughts yet).
Small note: what's with the Rey panting for the first few seconds? I know it's probably trying to evoke her feeling the Force for the first time on Ahch-To, but I found that a weird and unnecessary way to start the trailer.
Luke's narration feels repetitive, like ground we've already covered. But again, it's a teaser, so they have to kind of focus on the ground we've already covered to get us excited for what's coming next without actually showing us what's coming next. And then we have the princess theme playing even though we know that there can't be much Leia in this film--but it stands to reason that her role would still be significant. Rey's outfit at the end there is a combination of her standard look and the Leia white robe/dress (it's the color plus the hood). So we can assume that when Leia dies, Rey in some way assumes her role. And what was Leia? Hope and a leader.
I don't care for the whole long buildup to Rey flipping into the air to spear Kylo's ship (that is his ship, right?). Sure, some action's good in Star Wars, but it shouldn't be the focus (again, it's just a teaser trailer, so this doesn't mean that it'll be the focus in the movie itself). And weren't some of the silly flips and all one of the things that made the prequel trilogy a little . . . less than perfect to many viewers?
What I want to know: what do we see of Kylo in this trailer? Very little. We see more of Rey because we know what Rey's up to already so it doesn't disclose any secrets to show her. But what will Kylo do and what will happen to him? We see him fighting (presumably still on the wrong side) and we see his helmet being mended. Yeah, it's stretching things, but we don't really know that he and Rey were fighting--what if they were training together? And is he really the one mending his helmet? Isn't he done with that facade? It wouldn't make sense for him to try and put it together again, would it? It's broken and he's broken and now he wants his real rage to show on his face because he's done with putting up a fake facade of rage--he has the real kind now. So that does make me wonder if it's someone else--or if there is a specific, random reason for the helmet to be put together again.
Because remember, artifacts have been very important in the sequel trilogy. The Aftermath books had all sorts of random characters collecting items that had belonged to the Sith for rituals, etc. Kylo kept Vader's mask as a sort of idol. What if the masks have something to do with the return of that laughter at the end of the trailer?
Of all the characters we all expected to see come in or return, the Emperor probably wasn't one. I keep expecting Vader or Anakin to come back in one form or another. It was always a question of whether or not Snoke was truly dead for good. But the Emperor? Unless, of course, Snoke somehow was the Emperor--but the books seem to disprove that and put him as a separate persona. I mean, unless somehow it isn't just Jedi who've achieved balance in the Force who can appear as Force ghosts. Maybe the Sith have a way of returning as dark spirits--maybe that's all we see. Or maybe the laugh is just part of a vision that Rey has.
That title? I don't like it; it doesn't roll of the tongue. I guess it doesn't need to, though; we'll all just call it Episode IX, anyways. I don't think that the title is confirmation that Rey is a Skywalker. We've covered that. It could mean that Ben Solo returns, that Kylo finally ends. But I keep thinking about how the art book for The Force Awakens mentioned that the first thing they did when beginning work on the new trilogy was to answer the question of who Luke Skywalker was. The Last Jedi was all about dispelling the myth of Luke Skywalker. Maybe this film will be about bringing the myth back, in which case The Rise of Skywalker refers to the return of the myth. So Rey could in fact be the one continuing the myth, becoming the new figure that carries on the hope. Or it could still be Ben, or Ben and Rey together (or their child . . . oh, it's just one film, okay, maybe not, that's fan fiction, eh? then again, the whole Force bond thing was literally fan fiction, too, and that made it into the film).
So I don't overly care for the trailer itself. But I suppose it did its job of giving us a little tease.