I noticed a number of threads about tag management as well as few tickets, and this stage of development might be a good time to address it even. So I made a quick little mock-up, and also added the following to two tickets as I'm not sure how active or useful the forum or bug list are. So, here it is:
I'd like to have more tag functionality also. (This also goes with ticket #2421, #4577 and possibly #3836)
Mockup:
You can sort the list by name or count, and can limit the list to match the search box term(s). When you click on the Rename or Merge Tags buttons, a dialogue comes up that allows you type in what you want for the new Tag. Merge Identical would auto fix capitalization problems (possibly other things), and the check box indicates to automatically do this whenever importing new books or fetching meta-data. Maybe that should be a preference thing and not on here, though.
Any other comments or suggestions to improve tag handling would be awesome since I think it is really a pretty major part of how large libraries get managed, sorted, and looked through.
Edit: Actually, I just thought another useful function might be to "split" a tag, so something like "Fiction & Action" (a weird one) could be changed to have a tag for "Fiction" and "Action" (could be more than 2, just ask if there is another after each one entered). It would need to be in addition to rename and merge, because if a book didn't have either of those tags already, a rename or merge would give it only one of the two, then you'd have to go back and find all the books affected manually (not even possible probably) and add in the other tag. It would of course need to automatically remove duplicate tags when you do this, or rather just no apply one of the new ones if it already has it.