I love clamshell designs for pretty much any device. I would love a Switch that can fold. Much, much easier to carry arround.

Can you show an example of a successful or good VR that doesn't have a dedicated headset? Drop-the-screen-in VR are crap.

How are you going to achieve tracking? Towers and joycons enhanced with ping pong balls? Fingertip tracking?

Why put the console in the headset when you could have a HDMI wire going from the portable console to the headset just like we do when we listen to our devices with headphones?

Remembered me of one of my brainstorm designs of a mini switch (before it released), but not exactly clamshell, the upper screen slides in front of the below screen.
The joycon was detachable and could be put on both screens, so you could still 'switch' (keeping the feature of the name of the console) between 3ds(open, with the joycon on second screen), switch (a priori, closed, with joycons on first screen, but could be played in any configuration as well) and to carry/touch only (closed, and joycon on second screen, behind the first screen), which i suppose it could also play nintendo mobile games.

I don't think this would be a good move personally. Just the fact you'd be ruining the control sticks is too much of a hit - circle pads are an inferior control scheme, yeah it did the job on 3DS but still was an issue on that console for me.

They should keep it on the same track it's on. The only real drawback is you have to buy a case but that at least adds customisation and extra ownership of the console so it's a worthy cost to have.

The problem with that is the headset then needs its own separate LCD displays and that increases the cost of the unit a lot. Expensive add-on means its likely not going to take off much more than PSVR is, the key is to keep the price cheap. 

With just a plastic headset + some sensors integrated into the headset, you can have a much more affordable headset like say $89.99 with a game included. But if you're talking about a device that needs its own LCD display, you're probably talking $199.99 for the headset itself which is too expensive. 

Low price + low bulk helmet I think are the two keys for making VR a success, no ones really offering that with good software, Nintendo could be the first. 

You don't need fingertip tracking to have fun VR experiences, Labo VR pulls it off reasonably well enough and that's a very low end implementation. 

People will really love Mario Kart VR I think, Pilotwings VR would be crazy too and a Mario VR platformer would be a wonderful new leap for the franchise, probably the biggest since Mario 64. Astrobot was a pretty good game, but I think the Mario team can better that (much like Mario 64 blew away Jumping Flash and other 3D platformers of the mid-1990s).