Now I have N accounts and message whoever I like with those N accounts.
Basically, a site has to offer something to both women and men to do better than OKC. That proposal just puts a minor speed bump in front of men. As a group, men have few compunctions about abusing sites in order to get what they want. Multiple accounts to spam women is not a significant obstacle.
Nah. Someone writes a script. It becomes a browser extension. Now it's zero work. Women abandon your site, because the experience is no better than OKCupid. Men follow suit, because they tend to go where the women are.
Basically, your approach is the functional equivalent of DRM. With all the problems that go with that.
That still takes effort beyond just signing up. I think you're overestimating the willingness of the average guy to either script something up or go out of his way to find a browser extension. Most people's knowledge of browser extensions begins and ends with AdBlock anyway.
Basically, a site has to offer something to both women and men to do better than OKC. That proposal just puts a minor speed bump in front of men. As a group, men have few compunctions about abusing sites in order to get what they want. Multiple accounts to spam women is not a significant obstacle.