It would be great to have the option to sort by “tag only”. As someone who proxies and is pretty particular about printings, I really dislike accidentally printing a deck with cards that aren’t my preferred versions.
Ideally, I’d love to have two sections: one with a tag like “Printing Set” and another for “Untagged Cards”. This would let me easily copy all untagged cards (those without a preferred printing selected), set the printings I want, re-import the deck into Moxfield, and then apply the tag and preferred printing.
That way, when I build future decks, a large portion of the cards would already have their printings pre-set, so I wouldn’t need to double-check or change them again.