The original release of Link's Awakening occurred at a time when developers didn't mind experimenting with mechanics and story lines, and the game's plot demonstrates that willingness. There is a strange dream world here, and there are no real villains, plus there are parallel characters like Chain Chomps and Goombas.
However, the plot of Link's Awakening does not feel fully developed. This is not too surprising, since early '90s games weren't exactly known for their in-depth storytelling, but the amount of material available in the game makes the Switch release a perfect opportunity to create an even more compelling narrative.
Take the Wind Fish itself, for example. Players never really find out how it's connected to the dream world, why it has the power to wake Link, and what relationship it has to the orchestral instruments he gathers during his journey. All of these areas could be elaborated in the new version.
An expanded narrative could also mean more development for the Nightmares or even the inclusion of a central villain. Dethl is a neat play on the dream idea, but it seems like it exists only to fit the overall motif without having any actual motivation — not even Ganondorf's typical desire to "take over the world."
Again, the plot works just fine for the Game Boy and Game Boy Color versions of the game, but leaving it alone for the Switch release could easily be seen as laziness disguised as being faithful to the source material.