I can see the Wii being added down the line to Switch 2 as the functionality needed to play Wii games I believe is already built-in to the joy cons/pro controller. I could be wrong on that.
The DS can technically be done by having both screens shown on top of each other on a single Switch 2 screen. That's how played DS games through the DeSmuME emulator, but I doubt Nintendo is interested in making that work.
As far as games I'm hoping will get added the most:
All Game Boy consoles - Gen 1-3 Pokémon games (HOW DO WE NOT HAVE THIS YET?!)
N64 - Super Smash Bros, DK64, Diddy Kong Racing, Conker's Bad Fur Day, Turok 3 (just because Turok 1 and 2 are already there) Star Wars Rogue Squadron, Shadows of the Empire, and Episode I Racer
GameCube - Smash Bros Melee, Wave Race: Blue Storm, 1080: Avalanche, Star Wars: Rogue Squadron 2 and 3, Kirby Air Ride, Mario Kart: Double Dash, and the Mario Party games.

You called down the thunder, now reap the whirlwind







