The question When developing a stage play, whose gender matters more? The characters' or the actors'? is asking, as I understand it, a question about gender representation in playwriting (within a specific situation).
In favor: The issue of representing women and minorities in fiction is a big and often thorny one. I've seen it rear up, in the context of writing craft and career - from literary criticism which deliberately examines the roles of women (like this and this), to 2009's RaceFail. Therefore, these are clearly topics many writers care about and pay attention to.
Against: On the other hand, these topics are hotly debated. They can be seen as both controversial, and highly subjective. More to the point, discussing these topics in the context of writing can very easily bleed into discussing much larger issues of feminism and racism, which would be far out of the scope of this site, and probably quite inappropriate to the Stack Exchange platform. I'm a little concerned that this runs against our "we discuss craft, not content" guideline - just as Writers.SE is a poor venue to discuss whether Glenn Beck's latest book is "correct," maybe we also shouldn't be discussing whether some particular writing is "feminist enough."