That really is my biggest issue with changing costumes, though, even more than the resource investment or the potential for immaturity. Why is Westernization inevitable? If Shaka is leading the culture game, why isn't everyone else wearing hide kilts? If Genghis Khan is leading the culture game, why isn't everyone else wearing deel? If Russia is leading the culture game, why isn't everyone else wearing cherkeski? On the one hand, everyone in suits shows a lack of imagination; on the other hand, Neo-Nazi Joan of Arc reminds me that I don't trust Firaxis' imagination...
More heirs also means more risk of wars of succession. You have to find a way to deal with unwanted heirs, like the Ottoman policy of state-sponsored fratricide or the European practice of sending extra heirs into the Church. (And then when things go unexpectedly you get Louis IX...)
I loved Punk Joan of Arc. Now you are making me sad. Lol.
But I think it could work. Marketing-wise, not sure about codes and graphics 

I explicitly referenced the depiction of Jadwiga being more tasteful so it's not like I gave any indication of being an iconoclast or aniconist. I was saying the specific portrayal of Joan of Arc in Civ3 was irreverent, not that portraying a saint is inherently wrong. Also your definition of a saint is remarkably Protestant; the Catholic definition is someone who is recognized as having an exalted place in heaven who can make intercessory prayer on behalf of the living.