You realize glasses-free 3D is impossible on a large screen, right? Even on the Switch display itself it'd already be really hard to pull off, if not impossible. Never mind a TV.
As for me, personally all I want is for their next console to be a straight upgrade to the Switch. Same concept, same functionality, just better. More features, and all. As for the next system after that, well, I'm definitely not thinking that far into the future right now.
I think generally, Nintendo would be better off, if they tried an innovate-improve direction. Meaning: withone console they innovate, then they improve upon that concept.
They innovated with the DS. All the innovation the 3DS brought fell flat (mostly the 3D stuff), but as the 3DS itself was still an improved DS, it was still sufficently successful.
The Wii was a great innovation. With the WiiU they tried to innovate over the Wii, but it fell flat, and the WiiU itself was no improvement over the Wii, as it didn't even packed the main controller (you only could connect your old Wii controllers).
So if in the future Nintendo simply tries for one gen to improve on a successful concept, instead of trying to come up with something new, that should work. After one additional gen it is time tocome up with something new.
The Wii U was a bit different than the Wii, while it took the branding, it differed in the following ways:
* 4 Wiimote local multiplayer focus replaced with 1 big Gamepad.
* Asymmetrical gameplay instead of symmetrical gameplay.
* No major first party games until the very last game.
* No big releases for motion gaming (Just Dance on Wii U was the inferior B-version; while it was virtually the same game, the Wii version could be played on every Wii and Wii U, while the Wii U version was only playable on Wii U).
* The on screen gaming was another flawed concept because it divided the attention, it was intrusive to switch between Gamepad screen and TV. This is the opposite of Wii which probably had the least intrusive interface a console has ever had as the interface added rather than divided.
* Most importantly, Wii U tried to focus back status quo, while Wii was an art-house gaming revolution. It successfully challenged the status quo of Hot New Game = Same-old formula + upgraded graphics and sold nearly 1 billion pieces of software and over 100 million hardware units. While pretentious people trying to be gaming snobs (pathetic, I know) try to deride them as shovelware, the Wii game lineup proved to be a winner, as it went through the hottest period of any console in history - the "Wiimania" period where Wii was constantly sold out and selling for 600-800USD on ebay, regularly. The 2008 calendar year sales of 26 million still mark, BY FAR, the best sales a home console has ever had in a single year - to put this into perspective, that's almost double the Wii U lifetime sales. While the Wii U bought vanilla third party multiplat experiences (You know, the Ubisoft, EA, Activision type of games with lots of flash and no soul), the Wii brought exotic seeming new versions of games upgraded with IR or accelerometer controls which often improved the game into a fresh feeling experience (Tiger Woods, Scarface, Resident Evil 4, and Godfather felt like HUGE upgrades over older versions thanks to IR controls, I think the old GTA games would have been great on Wii).
Aside from that, Wii had a multitude of fresh new art-house style games like Cave Story, Wii Sports, Wii Fit, Endless Ocean, Little King Story, My Life as a King, Just Dance, Trauma Center, Anno, A Boy and his Blob. While Wii U had a few of these, like Trine 2, it wasn't much more than the average console, and they never felt a major part of the console's DNA like they did on Wii (and DS, and do on Switch); people often deride these as "shovelware" but these sorts of games are where creativity and innovation happens.
Sorry, I know I got a bit ranty (I tend to devolve into that).