Lets get a new 2d game before we start thinking about spinoffs.
A new 2D
Zelda is a must, absolutely. One thought I've had on the matter combines some particular Switch functionality with Aonuma's stated desire to rethink single-vs-multiplayer as a series convention, all while answering some certain fan requests.
In this concept, the player controls both Link and Zelda simultaneously, each character mapped to their own Joy-Con™, requiring the use of both to properly solve puzzles, traverse the world, navigate social encounters, and engage in combat -- all while allowing for
instant single-to-multiplayer action.
In any case, this feels exactly like something (Switch-era, in particular) Nintendo would invest in.
[...]
Hold onto one Joy-Con™ and hand the other off to a friend, relative, significant other, or random stranger you just met on a plane or at a rooftop party. Share the Joy™.
This would, of course, be treated as a full-on mainline 2D title and thus doesn't quite fit into the topic of spinoffs.
One idea that does fit into that category, however, follows from the
Cadence of Hyrule school of thought, where an indie title was allowed to translate its concept into a
The Legend of Zelda setting.
The title under consideration here is former Apple Arcade exclusive
Bleak Sword.
For spinoff purposes, it would likely take its high-octane retro-inspired diorama scene concept and structure it more akin to a
Zelda title. Now there are scenes that are focused on combat and scenes that are focused more on puzzle-solving
(puzzle dioramas similar to the earlier Zelda-based Captain Toad), put together in a manner that vaguely emulates classic
Zelda structure, each diorama scene analogous to the individual rooms of old
Zelda games.
Something like this would likely retain much of
Zelda's prestige aura, a more indie art house take, if you will.