There are lots of requests popping up to blacklist meta tags. Could we get a feature for 10K users to propose and vote on tags for the blacklist? (And, maybe, to un-blackist tags, too).
I'm putting this in an answer so I don't make a ridiculously long comment.
With regards to the other question, this part of the feature request was definitely
Regardless of my comment on Jeff's answer, I've mostly come around to his thinking on this. It really is a dangerous thing to be blacklisting tags.
However, I think it's reasonable that moderators (diamond mods) should be able to manipulate that system, for one simple and very important reason: moderators are the highest level of authority with domain knowledge for the site (in the general case). The fact is that having a moderator delegate to a developer is an unnecessary extra step, because in most cases, the developer can't validate the request anyway. (Now that I think about it, how would this process work for the new Stack Exchange sites?)
What form would a moderator-only system take? It could be a proposal/voting system with a low quorum (say, two mods have to agree to add/remove a tag to/from the blacklist), or it could simply be a list. But I definitely think mods should be able to manipulate this system.
Please allow us to vote up or down, not just approval.
It's so frustrating not to have down arrows when you have up arrows.