The slash genres

I'm not sure if this had been discussed before, so if it has, let me know.

The genre divisions on this site are, for the most part, very well-done, but there are a couple of genre designations that I really don't understand - specifically, RIO/Avant-Prog and Experimental/Post-Rock. In both of these cases, two distinct genres with their own unique definitions and characteristics are, for some reason, grouped together, which only serves to confuse a lot of people. The differences between the genres in question are made obvious on the genre pages themselves, where each of the grouped-together genres is given its own seperate description, but without reading those particular pages, the differences are not apparent and that causes confusion. As a result of this I've seen people thinking Ulver is a post-rock band or that Frank Zappa and Mr. Bungle are RIO bands. To avoid this kind of misinformation being spread, why not just separate the genres? I know it woult make some of them significantly smaller, but it would make a lot more sense, I'd say.