Removal of the Same-Sex Pairing category.
Imagine for a moment a theoretical archive of Harry Potter fanfiction. Pretty similar to the one MNFF has here - stories split up into categories like Romance or Post-Hogwarts or Marauders or what-have-you - except with a separate section for the stories that deal with romantic pairings between characters like, for example, Dean and Luna, or Cho and Harry, or Lavender and Parvati, or Blaise and Pansy, on the basis that such a pairing is mixed-race. Naturally, you'd get people on this theoretical archive that are very pro-mixed-race pairing, talk about how good it is that JKR included touchy social issues like this in her series, generally be big advocates of it in real life. And you would get other people who would say that they don't read the stories in the mixed-race Romance category because "they're just not that into those stories" and are content to leave things at that.
Does such an archive exist? No. Of course it doesn't. To modern, Western eyes (and I can assume that all of us here, as affluence, computer-owning, Internet-access-having individuals that we're all at least familiar with Western ideals), that sort of segregation is ridiculous in the wake of events like the Million Man March and the 2008 US election. We don't have that kind of systemic separation any more. The world has changed.
Change is an interesting thing. To many people, change happens with big sweeping events: one individual that stands up and speaks out about a wrong in the world, and the world listens and then change occurs. This is also the way many activists see the world - that they've got to make everyone aware, all at once, about all the things that are wrong in the world, and change them, all at once, right now. That's not practical, nor is it how change actually happens. Change happens over time, gradually, with very small steps. It happens when people are more and more exposed to an idea not as something different or as a curiosity but as a normal part of life. That's why there's no HPFF site that tags stories about Dean/Luna with a warning because of the mixed-race coupling. It's become such a normal part of society that we don't have to warn people about it any more.
So here's my proposal: get rid of the Same-Sex Pairing sub-section in the Romance category. Give the two biggest individual slash pairings (Harry/Draco and Remus/Sirius) their own place underneath Romance, and move the rest of the Same-Sex Pairing stories into Romance > Other. Keep the Slash warning - that gives people both the option to search for and avoid slash stories on their own terms - since it's not confining the stories focused around a same-sex pairing to one part of the archives. MuggleNet Fan Fiction accepts slash stories to its archives - that's a big step in the right direction already - and I'm asking it take another small step along that road by making the slash stories it hosts equal with and not separate from the opposite-sex pairing stories.