Since locked questions cannot be edited by anyone but a moderator, and (especially for historically-locked questions) many are off-topic, they have a higher incidence of bad tags.
My request is simply to put the same reputation requirements to using tags just barely kept live by locked questions, as for those completely unused.
This combines the advantage of keeping them for categorization of off-topic questions, and still effectively allowing their removal for new question.
"philosophically Historical Lock questions are deleted"
I think it's about time to extend tag creation privilege requirements to tags that have only locked questions.
This privilege was introduced in order to prevent (re)creation of troublesome tags by inexperienced users. Back then (long time ago), there were probably too few locked questions to make much of a problem in burnination efforts.
Working around locks by reaching out to moderators to delete tags from historical questions still was semantically not OK mind you - because very purpose of the lock is to leave old question alone and not bother with maintaining it - but it at least happened infrequently.
Nowadays, it is anything but infrequent, and weirdness of the need to edit historical questions becomes more and more prominent. Which is not surprising, if you take into account that amount of historically locked questions grows as time passes by.
There are already almost 2,500 locked questions at SO and almost 700 at Programmers. These questions span hundreds, if not thousands, totally arbitrary tags. As I wrote above, it already started to interfere too much with burnination efforts, and it will only become worse as more questions will get historical locks.
Regarding wikis for these tags, I don't see much harm in keeping these around (as sort of epitaphs?), although it looks more reasonable to delete them. I mean, since we're not supposed to maintain historical questions, it is hard to make sense of maintaining tag wiki involved in these.
Obviously, I concur with all those saying my idea is good.
Though after further consideration, I'm not sure it actually goes far enough:
Unless moderators and community managers consider nuking everything in a tag that has no open questions, and I think that would lead to a huge outcry and is seldom actually defensible and a good idea, we have to deal with tags without open questions.
As those tags have been judged as not useful for on-topic questions, or at least as no more useful than non-existing tags, we should have a privilige-check and a warning there too.
A dataexplorer-query to show which tags would be impacted (up to 82 on SO today):
https://data.stackexchange.com/stackoverflow/query/353581/tag-health
And the results from today as a CSV-file:
https://data.stackexchange.com/stackoverflow/csv/456364
I agree with this.
Tags that are old and unused take up unnecessary space that could be used for newer, better tags. With locked questions, all tags that are used by the question are subject to be removed. Of course, some and most of the tags will have to stay or it will ruin our questions forever...
Tags are subjected to be removed after x days of creation with less than y questions used in. Then the tags will go to a review queue specializing in no-longer-needed tags. Mods and users 20k and up (that is an estimate) can decide whether to remove or not. Tags that are removed must be approved by 3 or more people to continue.
This should only apply to graduated sites and public beta sites launched after z days so younger sites can have the chance to create and decide on the tags that need to be used or removed. This is my suggestion.
