Something I've wondered, but I wonder if we could organize some character tags from magical girl series using the _(all) suffix like with the Fate series characters. (speaking of which, I saw discussion in that topic implying that magical girl forms should be general tags, but that was before the _(all) thing happened).
Many posts already are tagged with two tags for one character (like post #3474913), so the total amount of tags wouldn't change in most cases, but it would help prevent people from missing posts because they searched with the wrong character tag, while also giving people the ability to search by identity (which currently is difficult to do if not impossible in some cases).
Plus, it would help with some characters with multiple identities - Sailor Moon alone has five character tags, and Precure has a few characters like this, for example.
Things to consider are spoiler prevention and what the 'default' name would be.