It is extremely important to not just graze the top of the barrel for the most recognizable leaders, ignoring what really went on in those times. "Not thinking about gender" and then selecting pretty much all male leaders is exactly the problem: this is known as unconscious bias, which is something that we have to actively work to overcome as a society.
I will admit that I am not one to actively look for strong women in history, but I think thats because I already know they exist. History, however, is predominantly patriarchal and despite what women may have been in the back round the fact remains they were not usually the decision makers or movers-and-shakers. It is in that sense that I do not seek to find a female for certain roles just for the sake of finding a female. But I'm a guy, so what would you expect?
That said, I would not bat an eyelash to see Martha Washington as the American leader, so long as it is her personality that is guiding America in game and not just for the sake of saying "oh look! We're diversified now!"
History is already filled with embellishments and bias because most official histories were written by people in power who had their own version to tell. Today, we seek diversity (never a bad thing in and of itself) but sometimes we swing the pendulum too far the other way as though it will correct the mistakes of the past. People like Martha Washington and Abigail Adams were very strong women, all the more because of the society they lived in. What I personally find more interesting than what influence they might have had on the men who *did* make the final decisions is speculating on how differently they would have done things. It could have been magnificent, or it could have been disastrous (because female or not they were still only human) but having an America in our game guided by either of those personalities would be fascinating!
I suppose, in the end, I am the worst at developing criteria for leaders precisely because I never seek to include anyone based on gender, race, ethnicity, religion or anything beyond what I feel they can bring to the game. So if someone shows me a leader I am unaware of and I do a bit of research and find them interesting then I am all for their inclusion.
I look at the above list and find it generally lackluster for a number of reasons and never once thought it was too Eurocentric, too androcentric or too any-centric. I don't look at a list and think "we need to fill more slots with x, y and z to make it better." Had the above list been all females from all southern hemisphere civilizations I would have been happy as a clam. I would not have despaired over the lack of ...anything.
Its funny, if Civilization had originally come out with all females leaders and not a single European civ, I would have said nothing, I would have enjoyed it and been quite happy. If someone then complained about the lack of men or Europeans, I would have had the same sentiments I do now. Don't pick your leaders and civs BASED on gender and ethnicity.
Now one criteria that is of some interest to me when it comes to leaders is how closely they are associated with the civ in question. Sometimes, for me at least, it is not simply about their power or forcefulness or what they accomplished, but whether or not they became an enduring symbol that, for good or bad, can never be divorced from their country/empire. This is why I never balked at Cleopatra as leader for Egypt, nor Victoria (despite her very real status as a figurehead) for England. Victoria was, quite literally, the face of the British Empire for longer than most anyone ever ruled a realm in history. Elizabeth, however, goes down in history as one of the most powerful rulers of any gender, of any nation in all of history. Elizabeth also meets the criteria of forever being an enduring symbol of England and would be my first choice as leader for England.
It would, of course, not be hard to do some research and find female figures throughout history to be leaders for most any civilization we can come up with. I just don't like doing it for gender sake alone rather than what bubbles up organically on its own. Whatever we do for the sake of some "anti-bias" becomes a different sort of bias all its own.