I'm sorry, there aren't any good f/f relationships in this fandom that people are passionate about, it's a shame. But there is a REASON those same pairings get written over and over, and it's because people like them. Whether it's because they have better canon relationships or everyone is just obsessed with dicks I can't say, probably a bit of both. You can't say it shouldn't have to be a niche like people are purposely ignoring the idea as part of some anti-lesbian agenda, when really people are just writing and commenting on what they like.