I know that I already wrote meta involvement. But I feel this is a specific issue that merits a separate answer.
Tag management [and maintenance] involvement.
I think that more users should be involved in the tag management issues. And not just the big ones (namely, the dissolution of the homework tag and other similar occasions). But the smaller ones. There is a very few people who bother to check out and weigh in on the majority of minor tagging issues. And this is a problem.
The top three [ordered by activity] answers on the tag management thread are all issues raised by me, who were there for. And after several days, butthey still haven't received very little if any substantial feedback (if any at all).
Tags are particularly important, because tags are more or less the only tool we have to consistently sift through the sand and highlight/ignore topics of interest/disinterest. If someone chose to tag a topology question with basis and nothing else, then all those people who follow general-topology will not haveare less likely to see the strong visibilityquestion.
So the fact people are less involved with tag management actively contributes to questions not being seen by the right people, or getting a proper answer. It also means that we are creating a repository of knowledge, rather than a database of knowledge. Databases have some sort of internal order structure, and bad tagging is the destruction of this structure.
And in addition, it really bothers me that a lot of established users interact with a question without retagging it. Sure, it happens to most people that they are not sure how the tags should be modified, but sometimes it's quite obvious and people still ignore it (e.g. a user who answers set theory related questions, but rarely retags a question about intersection from set-theory to elementary-set-theory).
Retagging, and in general tags management is an important part of exposure, searching and classification of questions (and answers). And I wish more people would take it more seriously.