Despite the circuit tag wiki saying "This tag is nearly useless" and "nearly useless. Consider using more specific tags to narrow your question down." -- which would seem to discourage its use -- the circuit tag is one of the most popular tags (currently the 10th most popular). But just quickly scanning the newest circuit questions, those that are tagged only circuit with no other tags either seem to be poor quality questions, or could more accurately be tagged circuit-analysis or circuit-design.
Passerby kindly provided a data analytic link for single-tag circuit questions: http://data.stackexchange.com/electronics/query/372728/find-questions-with-a-single-tag-now-case-insensitive?Tag=circuit
I initially thought questions that are tagged only with the vague circuit seemed to actually be about circuit analysis. But several of these questions are asking for help with circuit design, so maybe circuit-design should be re-activated.
- unlock circuit-design and use as a complement to the existing circuit-analysis
- lock the vague/"nearly useless" circuit tag to prevent new questions using this tag
- gradually retag the best single-tag circuit questions
- retag only a few at a time, to avoid spamming the "active questions" page
- most of the circuit questions are really about circuit-analysis or circuit-design
- delete any useless circuit questions
- repeat until bliss is achieved
- change the tag wiki to declare that circuit really means questions about how to design circuits, and to use circuit-analysis for questions about how something works.
circuit is one of the biggest tags, and will probably need a lot of time and effort to fix. But these "please don't use me" tags remain an attractive nuisance as long as they're available.
Interestingly, this very topic was discussed way back in 2011 at the dawn of time, when both circuit and circuit-design were removed. It's not clear when or why circuit came back while circuit-design did not. Remove circuit tag?
(Note: an earlier version of this request was posted 2015-10-08, but was subsequently deleted to avoid pulling focus off another tag discussion. Since then there's been more tag cleanup requests so I think it's worth opening to discussion.)