OP has some good points; I've been thinking along the same lines. The Switch, like the Wii U before it, appears to want to be a jack of all trades and master of none and this is potentially a huge problem.
Your best point is the one on portable local multiplayer, the whole prospect is ridiculous and focusing on small, detachable controllers and people trying to peer into what is basically a tiny display in hot seat gaming instead of online multiplayer, which the device itself would be much more suited to with its form factor, is a huge mistake imo.
And what about multimedia? If it can't use the same media functions as other portable and smart devices, why would people be hassled into carrying yet another device with isolated function? There are no news on this bit either, it's like they still don't understand how the smart device market and customer work. Look at what people do on the subway, the bus or on airplanes; they browse the web, listen to music and play simplified games with ditto control schemes for tiny bouts of easy fun. Does it even have a camera? Tablets and smartphones do, and they are used. A whole lot. Online functions, social media, share functions and the like are alpha and omega in the success of modern portable devices, this seems to have flown right over Nintendo's heads.
How many will, realistically, sit on the subway or the bus flailing around wii like remotes and play an immersive open world RPG like Skyrim or Zelda rather than enjoying in the comfort of your own, quiet home with a huge screen and great sound and better controls?
I feel like Nintendo are trying to tread down paths that are already heavily trodden and then they suddenly veered off and got lost somewhere along the way, once again. They need to get out of these woods and they need a device that is likely to have global impact, not just a shot at being a factor in Japan.
They still seem not to have learned how to properly read the market and respond, they still insist on inventing needs that no one, or at least very few, actually have and the concept, like the Wii U, is trying to reel in two very different demographics, which is a bad idea in the modern market, they only need their own example from the 8th gen for reference.
Edit; Poster above me knows what's up, it ties in with my example of Zelda and Skyrim on the subway/bus.