Probably there will be a resurgence of point and click adventure games pushed by the new mouse functionality (or even republish some old sierra/lucas arts stuff with mouse support).
Also may be useful for pc ports like simcity clones and strategy games (i could use that in civ).
Some propietary nintendo stuff will use it like mario maker or wario ware, some zelda dungeon probably will have a gimmick around it. And also some small indy third party stuff, like i don't know, mini motorways, things like that, will be built arround it.
I would like the command & conquer/red alert remaster on switch.
Maybe Microsoft releases aoe2 since they are open to release games on other platforms now?
The current motion controls for the pro controller work well, but a mouse + single hand controller setting could work as well.
It will make for an interesting dynamic for games with cross-play with other consoles where implemented though.
Dealing with Switch specific gyro info, sometimes coming from two sources sometimes from one must have been a PITA, especially for games using a cross platform engine.
The idea of controlling a game with two mice is suddenly interesting to me.