Enough with the "meta tag" witch-hunt. At some point, this is going to start doing more harm than good; heck, it's possible we're already there.
An inappropriate tag is a red flag for inappropriate questions
You think "discussion" is a bad tag because it's meta? Bah. [discussion] is bad because SO isn't a discussion site! Simply removing the tag doesn't do anything; there are still 400+ discussion questions hanging around. Either delete the questions with the tag, or leave it there as a reminder that cleanup is needed.
[code-golf] and [hidden-features] are great examples of this. Both identify things that, strictly-speaking, shouldn't exist on SO. They're not vague or confusing - both imply fairly strict standards for how the question will be asked and answered. I'm not a big fan of either sort of question, but if they're gonna be allowed to stay then we might as well classify them properly.
Discuss tags on their own merits
I'm having a hard time seeing a "meta-tag" classification for tags as any more useful than a "subjective" classification was for posts. Neither one helped to determine if the tag/post so labeled was useful or not, neither one was applied consistently, and if this discussion is any indication then neither one has an agreed-upon definition.
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