I think Miyamoto spelled out the direction of backwards compatibility and cross-gen titles pretty well here:
I’m of the belief that the majority of
new titles released after the new hardware will be exclusive to it, even within the first year. The next 3D Mario and Mario Kart for certain; and of course all the other major IPs like Animal Crossing, Smash, Zelda and Splatoon as they cycle in. If it launches after the new hardware, Prime 4 will be one major exception; the next Pokémon game (whatever form of remake / reimagining it takes) is another I can see as cross-gen based on Game Freak’s history; but I imagine the majority of cross-gen experiences would be ports, remasters or casual games with no real benefit in being exclusive. Any remaining Wii U ports like Wind Waker HD, Twilight Princess HD, Poochy & Yoshi’s Woolly World Deluxe or Xenoblade X Definitive Edition; the next Mario Party or even Tomodachi Collection; those types of projects. Not too disimilar from the lineup of post-Switch 3DS games.