High-reputation users tend to be more familiar with the site, and are more likely to add useful tags. Low-rep users often add the first tags they think of when writing a question. Thus...
Question: Can we sort tags by the average reputation of the user who added the tag?
Importantly, we count the reputation of the user who adds the tag (who might not be the OP).
To clarify, if some tag x is used, say, four times, with the users' reputation
1211 then it's average is
(1+402+402+1211)/4. And we create a list sorting tags by this average. (For practicality, I suggest using the current user reputation.)
I'm envisaging adding a button to the tags page thusly:
I feel this would help manage tags: if high-rep users are using a tag, there's almost certainly a good reason for it. If only low-rep users are using a tag, it probably needs maintenance.
It's a quick way to identify potentially useful tags e.g. when writing questions (when you don't have time to carefully scrutinize each tag). It's also a useful way to identify potentially useless tags (misuse-bait) when managing tags: it's an objective metric.