It would be interesting if they did an F-Zero spinoff that focused on Captain Falcon bumbling into various crimes and trying to "solve" them. 20% racing game, 30% adventures, 40% open world shenanigans ala GTA, 10% dating sim. Have Samus and Fox show up as guest characters.
when it comes to racing Nintendo only focuses on Mario Kart, but at least Nintendo is better at keeping its older IPs going or being regulars in other games than say Capcom is.
Valve is very willing to license the TF2 Mercs for use in other games. Dungeon of the Endless had several mercs as 'guest' prisoners. Several VR games use TF2 assets ... which will likely not include the mercs themselves ever.
There is a very good chance that Valve will bring the mercs into VR.