What do you think about the NS ?

[Soundwave]

I think it's a device of necessity for Nintendo. They couldn't have their userbase split especially in a way where their most expensive to make games (Zelda BOTW for example) is locked away from 80% of their audience (3DS owners).

They can't really compete with Sony/MS with a traditional console, especially since Wii U's failure gave the PS4/XB1 an insurmountable headstart,  so they have to go to what they're still half way decent at -- portables.

They can't support two distinct platforms anymore, not with rising graphics each generation, they barely made it out of the Wii U/3DS generation. That was a lot easier to do when the console was a Wii (GameCube tier graphics) and the portable was a DS (N64 tier graphics), if they kept progressing the portable would be PS3 graphics and the console PS4+ graphics ... not feasible to have two distinct libraries. 

They don't have a new "miracle controller" fad like the Wiimote because those types of things happen rarely in the game business (Nintendo didn't even invent the Wiimote, it was sold to them by an American inventor). So they can't do the whole "Wii" thing again, it doesn't work without a controller craze attached to it, as Nintendo found out the very hard way with Wii U. There is no new controller gimmick here and Nintendo is not even pretending there is one this time.

So Switch in many ways is Nintendo just forced into that position, there isn't really another logical hardware layout. It had to be a hybrid machine given all the above, it had to be portable given all the above, it had to unify Nintendo not only on one platform but behind their central strength (portables) because they don't have a miracle controller to sell the system with. 

That said I do get a bit of a kick out of people who said they weren't possibly just making one device, a hybrid wasn't going to happen, a Tegra wasn't going to happen, a Wii U tablet design wasn't going to happen, etc. etc. and Nintendo basically did exactly that.