I think there is a lot of valuable information left to be captured from the community in the retagging process that is lost if tags can be edited capriciously and if there isn't a formal way to discuss reasons behind retagging. Also, retagging is one of the few areas where participants in the forum directly conflict with each other, and so there is a potential for things to be adversarial.
It would be nice if there were requirements that retagging required reasons for the retagging and if each person is only able to delete a tag or add a tag once per question.
You label a question as "linux" and "bash" and "command"
I believe the question is generic enough to be appropriate for all unix variants, so I replace "linux" with "unix" and justify it by saying "not specific to linux, applies to many varients of unix", make the same edit for bash -> bourne-shell (same sort of reasons) then remove the "command" and justify it as "ambiguous tag".
Then someone else disagrees with me. Rather than start a 3 way fight, they delete "bourne-shell" (bourne-shell is itself an implementation of posix-shell), create "posix-shell" and add "CLI" with the justification "on this board, we label command line (vs scripting) issues with "CLI".
Now, if I disagree with this, and if there are limits to repeat tagging (can't add a tag that I've already added to a question, even it has since been deleted), my options are limited. If I disagree with the bash->bourne-shell->posix-shell tag, I can delete it, but if I try to retag it back to bourne-shell I'd get the error "you've already added that tag "bourne-shell"
All these comments would only be visible in the retagging interface, not when looking at the question. The people retagging the question would see the prior discussions of all the tags (and possibly not even see who did what retagging without further drilling into the interface).
Anyhow, I asked the question because I wasn't sure if the tagging discussion was overloaded with the question discussion, which it appears to be.