Answering on the overall topic of Switch trailer reveal very international and not aimed at the Japanese audience: while it's true that the ad features mainly Western people (more specifically, millennials) enjoying themselves in several ways while bringing the console with themselves, it's also true that we see the console used not at home, and its potential for both single player and local multiplayer.
Now, local multiplayer is big for handhelds in Japan (it's the very reason Monster Hunter / hunting games in general tend to fare much better on portables than on home consoles, for example), and this is a platform that allows local multiplayer everywhere at an even deeper level, since each unit comes with basically two mini controllers, for local 2-players sessions with one device (see: the Mario Kart segment), or local 4-players sessions with just two devices (see: the NBA 2K segment). Also, when you think about it, the vast majority of the trailer shows the console on the go, not even a minute is dedicated to its use at home, right because this is a "home console" that you can take with you at any time.
However, at the same time, the concept behind the "home console on the go" can be appealing to the West: the reason why Nintendo is calling it a "home console on the go" and not a "portable you can attach to your TV" is to make the proposition more attractive to the Western customer, and the whole reveal trailer was, as others said, much more biased towards Western audiences than what we would've thought. I mean, the mere presence of a 2K sport game and a Bethesda game (!) in the reveal trailer, alongside Nintendo titles is not exactly what people thought would be associated with an upcoming Nintendo console, be it handheld or home (or hybrid, like in this case).
So, no, I don't see the device itself being Japan-centric as others said, by the very nature of the device itself which tries to give an answer to the growing division between Japanese tastes and Western tastes. At the same time, right due to this factor, it has features already shown that can be very appealing for the specific Japanese reality that is so fond of local handheld multiplayer. Also, the ad contained Nintendo titles of course, and one of them was a Splatoon, which we can say is a bigger phenomenon (relatively) in Japan than elsewhere in the world (and the social media answer to the Splatoon Japanese's official Twitter account tweeting about the new hats clearly shows how relevant is the franchise for the Japanese audience).
We'll see starting from January what's going to be the Japanese scenario, I guess: the Switch Partners slide showed a healthy amount of Japanese developers, especially some that are not the ones you typically expact to appear on a Nintendo platform (From and NIS), and I'm fairly sure we'll see more regional-focused advertising as the launch approaches (by that I mean not just commercials shot in the West featuring Western people in several occasions that fit more their way-of-living, but commercial shots in Japan featuring Japanese people in several occasions that fit more their way-of-living). But (and this is a big but *I don't care about all the butt jokes, bring them all, I'm ready* ) we must see the kind of support the platform will receive in the first few months indeed, and hopefully it's good enough that, coupled with an attractive first party lineup, a good price and other stuff, will make the platform very attractive to Japanese customers. ...Such an easy task, right?
P.S. If possible, I'd like to go a bit deeper, on the matter of initial support for recent platforms, in the next future. It is an interesting topic, and a more informed comparison could be helpful to give a better context for posts on the matter.
Also, random YouTube stats: the japanese version of the trailer is sitting at 3,329,559 millions of views right now. The most viewed video in the Japanese Nintendo YT page is a Super Mario 3D World overview trailer with almost 4 millions views from 2013; the Switch trailer will become the new top video for views in the next future. And it's quite higher than the most viewed video on the PlayStation Japan YouTube channel, which is a Call of Duty: Black Ops III trailer at 2,632,114 views
