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BookJunkieLI - the only thing that comes to my mind is to use hierarchical tags, see ==>>
Managing subgroups of books, for example “genre”
I guess what you're after is a) a tweak to designate tags to be kept in the order that they're entered and/or b) an ordering feature (up/down green arrows) in the Tag Editor->Applied Tags list.
Slightly

I would also like a tweak that would pop the Tag Editor dialogue when a Tags cell is edited from the Book list (a'la the Comments Editor) rather than the current simple text edit box.
BR