Japanese overview trailer:
It confirms a couple things such as Team Skull still seemingly having a role and Kommo-o still being a Totem Pokémon. It also seems to confirm what the Chinese leaker said and at least some legendaries will be fought in their original area as Mewtwo's looks like Cerulean Cave, though it's only the hallways of course. I do say some though as Suicune's silhouette can be seen at one second behind a waterfall, which is nothing like either of the areas it's fought in (Tin Tower or Route 25).
So a few thoughts:
-I said it before, but from a gameplay perspective the Rainbow Rocket incident looks interesting and fun. The Villain leaders tend to be one of the most memorable battles of their games, so for that to be carried over to this would allow for a great post-game event. Story-wise, I can't say I expect much as there's a lot of holes in how the story could work, but we'll see how that goes.
-Surprised they used RS Archie and Maxie considering the ORAS battle models were present, but I guess that does add to the theory that the characters drawn from the other dimensions are their non-Mega counterparts (excluding Lysandre of course). Also, I'm happy they used Ghetsis from BW1 as I like his design and plan a lot more in those game then B2W2.
-I'm mixed on the Legendaries since it seems like it'll be falling into the same trap as ORAS where it's just 'here's a legendary we threw in for you, get it' with little build-up or lore to it, but I guess with how many there are it's to be expected. At least in this case it's implied they have special areas where they're found so they have some personality to their encounters, but I do miss when the hunts had a little story to it.
-Interesting that the Totem Pokémon will be available for capture, it's probably not going to be anything more interesting then just their sizes, but it's a nice incentive to go around and get the stickers.
So all in all, a pretty good trailer, so far it looks like it'll be a good send-off to the 3DS era of Pokémon.