So I merged tags, and it created duplicate tags. I came to meta to write a bug report and saw this question: Can the Batch re-tag feature automatically remove duplicate tags?
That sounds like what I want, but the answer didn't really address the question. Why should I go merge and then have to go do a second step of removing duplicates? If I'm merging tag-a and tag-b and a question is tagged with both tag-a and tag-b, I want it to end up with tag-a only and not tag-a tag-a.
I think the system even knows this is going to happen based on what was displayed on the confirm-merge page.