I didn't read this entire forum but just to get back to the original subject...
The main reason I see for having women role models out there is that it makes a big difference in encouraging other women to join up. It makes it seems like a safe environment that will accept women and treat them "equitably." After joining it doesn't really make a difference whether your role models are male or female as long as the training is good, although since smaller, weaker people, including women, often have to rely more on technical insights than brute force, they're great to practice with. (Although I know plently of brutally forceful little people.)
Organizational discrimination is another thing since it limits opportunities for everyone. We'll never know whether the lack of female senseis at the Expo was due to discrimination or mere clumsy oversight or lack of availability, but we should at least acknowledge that aikido organizations, like any organizations, are not immune to gender politics, unless they're like super unbelievably pure.