As long as someone is prepared to do a certain amount of verification work for admission to the forum, I can see this as being a useful thing. My only concern would be the amount of work entailed in doing verification, given the sheer number of men who turn intermittently into teenaged girls when on the 'net.
QD, I'm sure that your chances of getting something like this put together would be enhanced if you developed some minimum verification protocols and found a female moderator and/or admin for it.
I personally would have zero problem being excluded from the forum and think that it probably enable some discussions that don't currently take place. More importantly, if moderated properly, it would likely increase the number of active female ENWorld posters, an objective I'm sure we would all support.