I have only been a fan of anime since Spring of 2003, when I discovered Rurouni Kenshin and Yu Yu Hakusho. I discovered fanfiction that Summer. I had been reading gay-themed literature since I discovered Mercedes Lackey and Lynn Flewelling in 2000 and 2001. I read female authors for awhile, and then read quite a few male authors since I wanted gay mens' own perspective on their orientation and relationships. I was amazed by Yu Yu Hakusho. I saw it as yaoi right away, and the fanfiction came as no surprise to me. Another anime series I really like is Saiyuki. Its characters are smart, tough, and lots of fun.
Gundam Wing is my favorite show and has my favorite fanfiction because of the versatility and the depth the characters are plausibly capable of. I don't find many anime females all that interesting. Kaoru from Rurouni Kenshin is just a joke, and so are Relena and Noin from Gundam Wing. Kaoru is an overly-emotional thug, and the other two lose their wits entirely when their crushes are anywhere in their vicinities.
The philosophical bent to these anime shows makes them just a step above almost anything else I've ever found. I like comedy too, and they do have that (except for Gundam Wing). But I would swiftly lose interest without the maturity of these shows. Whenever fanfic writers go for the stereotypes overmuch without seeming to really know the characters as depicted in the shows (Duo is not stupid or a glutton, Trowa does talk) I really get mad. And alternative pairings for the sake of variety, ignoring the chemistry we see in the shows is just terrible. WuFei was aloof and disinterested in the show, Trowa and Quatre clearly shared a deep connection, and Duo clearly stated an interest in Heero early on after meeting him. And I would never have any of them sleeping with the enemy, although WuFei and Zechs could get together after the wars.
I don't like gratuitous yaoi either. Yusuke (Yu Yu Hakusho) calls Keiko his beloved to the younger Toguro, and Sanosuke (Rurouni Kenshin) talks about women and develops crushes on them. I can see him discovering that he loves Kenshin under a highly stressful circumstance, but not otherwise. Yusuke could plausibly develop gay tendencies in the Makai, and he has a very long lifetime ahead of him to do so. But he does love Keiko.
Yuri fics have to be plausible, too. In Gundam Wing, I only see Sally, Catherine,and Dorothy as convincingly potential lesbians. This is because the other main females all have huge crushes on one of the male characters, or in Hilde's case, comment on the attractiveness of a male character (Trowa). She could be bi, and so could Trieze.
Anyway, that's enough ranting. I'm done.