@aceina: People are making a lot of completely opposite assumptions about why Yabuki made a gender-bending manga with a M->F/F couple. Some are saying he wanted a regular F/F main couple but Jump wouldn't allow that. Others says he wanted a gender-bending series and the protagonist having a female love interest is some kind of concession to make it more "normal". Others are saying the main couple doesn't matter, and it's just a cynical ploy to get an obligatory self-insert for ecchi while drawing even few males.
Honestly, none of them hold water. Jump are about as likely to veto a GB M->F/F romance as a F/F one. An artist famous for "normal" ecchi was gonna get audience backlash for any kind of GB series. And if Yabuki wanted visibly all-female cast, he wouldn't have made a male rival. Until he states otherwise, I would just assume he liked the
specific concept of a romance between a girl and gender-bent boy, hence it stayed even after dropping almost everything else from the oneshot.
(Also, Matsuri right now isn't too far from being a transgender
boy: he presents himself publicly as female, but identifies as male despite having a female body. He'd be even closer if he identified the same despite knowing he could never change back physically, especially if he was open about it.)