So far we have open world action, racing, fighting, shooting, 3d Platform, 2D Platform, turn based strategy, and JRPG on or reasonably soon on the Switch. Figuring out what the system doesn't have gives us an idea of what they might do next. 

They don't have a big puzzle game on, though I am not sure what Captain Toad Deluxe would be like, for example.

Sports maybe?
Also, a bunch of fun mingames like WarioWare/Rhythm Heaven

What about the Payou payou Tetris game or whatever it is called?

Edit I guess that would be Puyo Puyo Tetris.

We have nba playgrounds for sports 

No first person shooters as far as I know.

I don't think covering all genres, or the best selling ones, are what really matters to gamers.
People like shooters, yet, they tend to buy more of the same. And that might just be the same for other franchises.

We are also lacking on nfl and soccer games, if i'm not mistaken.

A dating sim. Get on it, Nintendo.

Also, like Linear blockbuster Action-adventure? You know what I mean

Also, cool ADVENTURES, like Telltale games or 3d like Edith Flinch/Life is Strange, or Visual novels with cool script

1st person shooters,sport simulation games, horror games, a non-JRPG/SRPG with an intricate story and one of those 'games' with so little gameplay and so much attention to story that you can play them on youtube.

I actually hope Nintendo bumps up the horror aspect in Metroid Prime 4. Not in jump scares but in atmosphere.