Posted this on my Tumblr, but I figure I'd share my thoughts here, too. Trailer embedded in the post linked below, text copied here (with some edits).
https://www.tumblr.com/blog/view/avernale/685913897347219456?source=share
First notable things about the trailer are the Pokémon stickers on the wall I didn't notice before. Not much to say, just wanted to point them out.
Second is the new Pokémon Center, which is now... a gas station? I mean, that's what first comes to mind when I see it, but it's actually more of a kiosk now than an entire building. I'm willing to bet this is just how they are in The Wilderness, since I'm pretty sure there were traditional Pokémon Center buildings in the previous trailer. This is probably so they don't need to have NPC's in The Out Of Doors perform this function (though they still could if they wanted). It's probably also a PokéMart, PC, and other functions.
There appear to be two academies. Judging from the starting outfit thing, which you belong to probably depends on version. I get the impression only one will exist per game, but not necessarily.
There are also two professors in this game, but it's also one per version! Tron-reject Turo (short for Arturo, probably, but likely Turbo also. This may be more apparent later) in Violet and Unfrozen Cavewoman Professor Sada (seriously, what is she wearing?) in Scarlet. Also of note, the change in character art style indeed goes beyond the player characters.
After new footage of the starters (with more info on the website), we're introduced to Nemona. Judging from what she says, you meet her before you pick your first Pokémon. The website describes her as a guide rather than a rival, and I'm getting a "Sempai" vibe here. She probably goes to the same school as you as an upperclassman, which is a fairly literal translation of the word though I think it implies a sort of casual mentorship as well.
I also notice some asymmetry in her design with that single, elbow length glove. I'm betting either it or at least the bracelet part is the new Gimmick Band, like the Z-Ring in Sun & Moon or the Dynamax Band in Sword & Shield. You won't see it on the player character in either trailer, but they've left the Gimmick Bands out before properly introducing them in past generations.
Nemona also introduces us to Pawmi, which is probably the worst Pikachu derivation I've seen. It didn't even read as one until I saw it was an Electric type on the website. I see it now, of course, but this thing doesn't even have a nose! This looks like someone tried to reverse-engineer Pikachu for their own game and avoid copyright infringement as much as possible. I mean, you could say that about all the Pikachu derivations, but... What even is it? A red panda? A chinchilla? A chipmunk? It's almost shapeless.
Also, in-world multiplayer is back, but now it's less of pseudo-MMO free-for-all. You can link up with up to four friends and... go your separate ways? I mean, sure, I guess. I'm not sure if that's meant to be a selling point or just a framing device for the rest of the trailer. Also, it looks like trainer customization is back. Yay! I didn't really doubt it but I thought it seemed possible with the version-exclusive starting outfits.
After a couple more returning Pokémon (Fletchinder and Flaafy), we're introduced to Smoliv. Love the name, hate the design. It's like a knock-off Petilil, but I'll give it a pass for now since it's probably going to have an evolution that looks more interesting. It apparently produces oil that's not fit for human consumption, but I imagine Oliverybig's oil will be a popular cooking ingredient. But it can't just be a black olive, right? It's gotta be, like, a vine with black olives (or even Smolivs *shudder*) growing on it.
Next, we're introduced to Lechonk, who is the only named Pokémon in this trailer because we also get to see the battle interface. The interface isn't much to write home about, though I do notice angles in the corners that kinda makes it look like we're watching through a camera. Will Drone Rotom play a larger roll in this game?
Also, now that I take a closer look, I notice that while Quaxly's HP bar is in the lower left corner, Lechonk's is above its head. That is very much like Legends Arceus, which suggests to me that you can have impromptu horde battles against wandering overworld Pokémon in much the same way. Maybe more of that system is returning than I expected...
Also, Lechonk is the best of these three new Pokémon, visually. Still not great, but I like this little piggy better than Smoliv and Pawmi. Liking the name, too, though I feel it's a bit meme-y. Can't wait to see what porker this thing evolves into.
More returning Pokémon, a couple of which we get to see in the new trading sequence. Kind of a weird flex, but okay. It's notable in that completely done in some separate, glow-space cutscene, instead being shown flying from their trainers' hands in the overworld and passing each other in the skies above. Neat.
A lot more returning Pokémon (including some I think were cut from the other Switch games?) leading to what appears to be an outdoor battle court. My impression is that this is what Gyms look like now, though I could be misinterpreting things. I can't imagine that they're purely for having open-world PVP, though.
Oh, Pikachu's back. Okay.
Then we leave actual game footage as the camera runs through some kind of chasm, across some sea, and up a stone spire, splitting into two frames. And at the precipice(s) stand the Box Legendaries!
On the left, Scarlet's Koraidon, a red, serpentine, feathered lizard with what looks like a wheel in its chest. Clearly based on motorcycles. And on the right, Violet's Miraidon, a blue, robotic serpent with jets for legs! (I was calling them "Road Rage" and "Jet Blue" before I found their names) Personally, I'm liking Koraidon more than Miraidon, but I think I might need more incentive to get Scarlet instead of Violet.
We also get to see the box art, which has a leather-bound look it behind the effects around the legendaries. Now I'm getting even more of a fairy-tale vibe! Although, the Pokémon themselves aren't very story-bookish, are they?
Oh! And the release date! November 18 this year! For now, at least.
Then the trailer ends with a Pokéball flying across a shifting, crystalline background that suggests quantum foam to me. Will the multiverse play as big a roll in this game as it did in Sun & Moon? Does this foreshadow the "Villain" legendary? Or even the Evil Team? Or is it just how they end all their videos from now on? I wonder how long it'll be until we find out.
Incidentally, I was thinking about the Legendaries' designs and how they've been introduced, and I came...
...Up with an exciting theory!
...About these games' signature gimmick!
Pokémon On MOTORCYCLES!
Seriously, though. There's a old episode of the anime that featured "Extreme Pokémon Training," which was essentially chariot races but with Pokémon. I can easily imagine Jet Blue and Road Rage, I mean Miraidon and Koraidon in some kind of racing battle. It's probably unlikely and I'm not sure how it'd work, but it's exciting to think about!