I totally agree with OP. The Switch has a competent OS that's slick, fast, and easy to use, but I've never seen a Nintendo system so devoid of personality, and it's lacking the community-vibe that the 3DS and Wii U had. I mean, it doesn't even have third-party video apps like Netflix, an internet browser, or a Mic or Camera. You can't customize anything about the home screen. It's clearly built 100% as a games machine and nothing else (which is something Nintendo has said before, but it felt more like an excuse for lacking features then, as opposed to now where it's a deliberate choice).
It's not awful, like I can live with it just fine so long as the games are great (which they have been), but it's something I notice every time I turn it on. It's probably what a lot of people have wanted from Nintendo for years, but as someone who only really got into them with Wii and DS, it makes it feel like less than a Nintendo console for me, and definitely a step-back from where the 3DS is right now. Even just the vibes; posting Wii U screenshots to Miiverse felt like "yeah cool I can share this neat moment with my friends and other fans" but the screenshot system on Switch linking to Facebook and Twitter makes it feel like Nintendo just wants me to advertise for them, though that's probably just me being cynical.
I thought Dual-Screen gameplay was the thing I'd miss most with Switch, but an interesting OS with system-specific apps and a fun ecosystem may actually be the thing I miss the most so far.