Late to the docking discussion, but what would be cool and feasible I think is:
The current switch can be coupled with the NG switch through streaming -> Stream Play
Nintendo has often done interesting B.C. or sharing integrations on their devices.
(I'm just going by memory here)
- The Gamecube had a core focus with multiplayer, 4 controllers (double dash) and a unique Gameboy link to allow for some hybrid gameplay experiences or the GBA player, which allowed you to play GBA on your TV.
- The Nintendo DS, had DS Download Play, allowing you to share your cartridge with someone who did not own a copy of the game and enjoy multiplayer together. I think the GBA had something similar, but I'm not sure how many devices did it. 3DS continued this ability.
- Wii had a whole gamecube in it practically
- Wii U, dropped the GameCube B.C. hardware-wise, but it was still possible and they did a bunch of bespoke ports later on as Virtual Console became a commercial priority (so sad that mine are still stuck there ....). A-synchronous or off-tv gameplay was integrated well.
- The switch was a "hard b.c. cutoff" in some sense, unifying handheld and home console, but with no B.C. hardware or software-wise, initially.
- NG switch is the continuous iteration, like they somewhat had on their previous platforms before respectively (handheld & console).
So I guess the idea of streamplay is to allow some multiplayer/hybrid experience, where switch 1 or 2 owners can connect to a docked NG switch and play the game on their device (Splatoon, Mario Kart, smash bros etc.). This way older switch owners get enticed by the higher visuals and capabilities of the NG switch.
Moreover, I guess a limitation of 1 device would be in order as it has to send out 2 video streams (1 to the TV and 1 to a connected device).
Okay, that's it