I know this was brought up somewhere before, but I don't remember where and I don't think it was resolved.
I want to tag post #2502058, for example, with some sort of blush, because it's an important part of her facial expression and should be searchable.
However, I hesitate to use the blush tag because that dilutes its usage for such as post #2500902 where the blush is very pronounced and a primary visual element of the image. The one in my first example is far more subtle and not really the same artistic element, IMO.
In a third category are posts like post #2296902, which technically include a blush, but the blush isn't a meaningful part of the character's expression, it's just there's some color in the face. (It would look somewhat unnatural if there weren't.)
The blush tag is so diluted it's basically useless. When's the last time anyone actually used it in a search? It should be split into at least two, and IMO outright removed from some posts. There would obviously be a lot of work needed to fix old posts, but let's at least decide how it should be and start using that for new posts.