I think "If/Then" will go a long way towards remedying the dearth of lesbian characters on Broadway. The only thing that sticks in my craw about that relationship is that I can't understand why it would succeed in one timeline and not the other -- unless Elizabeth was able to help it along in one and not the other.
Speaking as a straight woman, I suspect that the greater number of gay male characters on Broadway comes from the greater visibility of gay men in the performing arts. For whatever reasons, gay men seem to be heavily represented -- probably overrepresented -- among performers. However, there was never a stereotype regarding lesbians' being artistic. Also, many lesbians fly below the radar because society always has given women more leeway to have roommates and best friends than it has men. Additionally, Leviticus, which is responsible for the religious right's knee-jerk reaction against gay people, does NOT say one word against lesbianism. All of these factors may have contributed to the greater likelihood of finding gay male characters in plays.
Audrey, the Phantom Phanatic, who nonetheless would rather be Jean Valjean, who knew how to make lemonade out of lemons.