Having read through most of this thread, albeit briefly, it seems the focus shifted to regularity and that we have chosen to be a fraternity. I would humbly suggest instead looking at why Masonry exists, as well as what it represents to many. As to why it exists, let us consider the three great principles of Brotherly Love, Relief and Truth.
Firstly, I understand Brotherly Love to be represented by Aristotle's Philia, or Philos, for which the great city of Philadelphia was so aptly named. It typically refers to affectionate regard and friendship, amongst equal brothers. The earlier story of the two brethren at the funeral is indicative. Unfortunately, us men tend to revert to our baser instinctual natures around the fairer sex. However, the happily married man can typically subdue his Eros as it evolves toward Pragma, the longstanding love between a couple. Yet, I would like to believe that we could relate to women as well with brotherly love, without Eros getting in the way. Perhaps our brotherly love needs to evolve to Agape, the highest form of love, charity. I'm not sure we're ready for that though and I doubt Masonry has enough gas in its tank to get us there....
Secondly, Relief or charity itself. This is clearly a win for mixed Masonry. I'm not sure about you gents but in my experience females are far more inclined to charity than men are. Of course I'm generalising and the times may be changing, but I believe that many more females still work in charitable pursuits than men do.
Third, Truth or the seeking of Light. To my mind this is once again a win for mixed Masonry. Clearly this is simply a vestige from the past, where only men were allowed to discuss the serious topics. And our world is likely the poorer for it.
I fully understand the notion that men need to escape sometimes. Masonry provides a path of initiation, of becoming a man, that us men lost a long time ago when we left our caves, and started the long journey to our urban boxes. Women still retain some of their initiatic processes in life, childbirth clearly being one of them. However, intellectually speaking I'm having a very hard time squaring the concept of not allowing women in anymore. Freemasonry has some real gems within it, which have stood the test of time. But we are entering a more enlightened age now and I feel the Regular Craft will be left behind.