I was really fond of Lost Kingdoms on Gamecube. Hm, maybe a new Adventure Island (just maybe).

So much said in this thread is of genres that never died out. 2D games,3D platformers,turn based RPGs all still being made often. If anyone says Shmups they would be wrong again as we keep getting new ones as well. beat em ups yeah kinda but Yakuza exists and the makers of Pier Solar are making a Streets of Rage clone. Light gun shooters exist but no light gun so there is that. Personally not seen any games like Another World or Flashback last 2-3 years. FMV horror puzzle games like 7th guest.

I want Nintendo racing games to come back. F-Zero, Wave Race, 1080, etc.

And Sim City type games.

I would like the racing genre to make a resurgence as a whole. Burnout, Project Gotham Racing, and Midnight Club, just disappeared out of thin air after 2007-2008. Nothing outside of Forza Horizon has interested me these days. This year looks like somewhat of a comeback though: Forza 7, Dirt 4, Project Cars 2, New Need for Speed, and Gran Turismo Sport (if it doesn't get delayed to 2042, that is).

I have an odd craving for a baseball game on the Switch.

Like old school style ala Baseball Stars or RBI Baseball for NES or the Griffey games on the SNES.

I was such a sucker for MLB Featuring Ken Griffey Jr. on N64. Did you ever try that one?

Red Faction and Saints Row.

On the N64 not so much, but I heard it was good. If I recall correctly the game kept getting delayed and I think I got pissed off and bought something else, lol. I had Kobe Bryant NBA Courtside for N64 though. 

Real time strategy games (C&C/AoE/Sup Com)

Beat em' up

Hack n' slash (DMC style)

Rail shooters (Time Crisis)

I really just want more PC based RTS games, nothing simplified or turned into a Moba like game.

This. But not the 3rd person Red Faction.  The classic 1st person, make your own path through a wall Red Faction.  And with new HW there would be less restrictions on that.  Also, want a Saint's Row more along the lines of the 3rd one.  Loved being able to save up a shit ton of money and make myself invulnerable.  Never laughed so hard as I did taking a swan dive off the Saint's Tower and surviving.

@ OP

I'd like more 3D adventure platformers.  I remember playing a game called Kingsley's Adventure for the PS1.  It was targeted at kid's, which then meant it had some hard as hell segments.  But, it was more action adventure than it was 3D platformer, with a little Metroidvania thrown in. I always thought if that game got a full remake with tighter controls, larger areas, and some extra content, it would be awesome.