^^^^^ exactly this!
Also worth nothing that when new fans are introduced to the band nowadays, the common entry point is something along the lines of Pet Sounds > Love and Mercy film > Smile Sessions/BWPS. That's how it was for me and a lot of others. Smile hasn't been on the level of 'obscure archive material' for a long time, it's their other most significant piece of work. And parts of it are still unavailable, or only out there in a mono format that doesn't cater to modern listeners (I know a lot can't be true stereo but the majority can), or in a configuration that mimics the 2004 live performance and doesn't necessarily represent the original intent for a lot of the songs. TSS is fantastic but if Pet Sounds can have 8000 anniversary reissues there's still a lot of room for unreleased Smile stuff to come out.
Additional "Smile" addendums will mean nothing other than to dedicated, hardcore fans. For new fans who get into PS and then "Smile", the *FIVE DISC* "Smile Sessions" boxed set is probably more than enough. Most fans that fall under that description are probably fine with the 2-disc "Smile."
Among those casual-but-deeply-interested type of fans, nobody cares that a bunch of the "Smile Sessions" tracks are in mono. The set won a Grammy, and I don't recall many if any critics/reviewers deeply criticizing the lack of more stereo mixes on the set.
"Do You Like Worms" sounds like sludge in mono or stereo.
A copyright extension set for 1967 would be a fine place for more "Smile" mixes, and obviously *I* would buy a "Smile Sessions Addendum" set. But I wouldn't really advocate for a wide, huge release to the masses of that stuff. Or rather, I wouldn't prioritize that. The "milking it to death" model for releasing "Pet Sounds" retrospectives every ten minutes isn't something I'd want them to follow for anything else in the catalog.
The "wide release" projects they should be targeting is stuff like a "Brother Years" set highlighting the *albums and albums* worth of totally-unheard material, a 70s Brian-centric set with demos, etc., deluxe sets for things like "Sunflower" and "Surf's Up", a great "Live" boxed set, and so on.