As someone who reads a lot of slash, there are two things that attract me that I don't commonly see in femslash (it might be in het, but as a primarily 'same sex' attracted gender queer individual, I find het too squicky), and they happen to be a little on the contradictory side. Both have to do with the age of the protagonists.

The first is the average age of the main pairing. While I can enjoy a teenaged angst/romance/other, I don't identify well with them. And the fandoms that have major characters my age tend to focus on the menz. The main exception to this is Rizzoli and Isles, but the fic is so hit and miss.

My contradictory one is that I like age disparity, and I'm mostly only finding things that aren't really sucky in Harry Potter fandom. This statement will probably have people rolling around laughing, as there is a lot of very disturbing under-age Harry Potter/Severus Snape fic set during Harry's school years. What there also is is a lot of older, post-war, desperately unhappy Harry Potter fic, which absolutely fits the bill.again, there is a single f/f pairing that also works, which is in The Devil Wears Prada (which again, very hit and miss).