The complexity has a number of meanings. Some of which are already covered by other tags.
In particular, the 100 or so questions seem to fall into one of three groups:
- Retag all the complexity questions about big o, as big-o
- Retag all the complexity questions about cyclomatic complexity, as cyclomatic-complexity.
- Leave the hand wavy complexity questions there
- Change the tag wiki to reflect that this is about hand-wavy questions.
- Get SE to update the tag guidance on complexity to mention the other two tags.