Yes. The primary issue I have with it is that the concept of getting new leaders every now and then is not really civ-like. For instance, at the start of the game on some speeds you would need multiple leaders per turn, using normal lifespans. The whole point is that your leaderhead is supposed to be a famous figure from your civ, not the leader of it. You are the leader of your civ. That is my main objection to this idea. If we want to have more diversity in AI leaders the route I'd pursue is to allow an AI's personality to evolve over the couse of the game. That and adding trait levels (I'll probably be doing that for my trait set next version) will help in that goal and also be fun.
In our planning discussions we've realized that not all players would prefer changing leaders even infrequently. Thus, yes, it'd certainly be optional.
You mentioned about normal lifespans and you're right about older eras and how that would work in any sort of 'realistic' worldview but like many other elements in civ, it would be a more subjective suggestion of reality we'd seek rather than an absolute reflection.
We figured it'd still be a bit 'more' real feeling to enable Dynamic Leaders even if those leaders still had a period of rule that far exceeds a normal established human lifespan. The lifespan of rule for a leader would likely be based on civic selections actually.
Like unit movement, its all subjective and the timing of changes like these would need to be admittedly unrealistic to make it work (we wouldn't want to have leaders changing every round or anywhere near that, no) but occasional changes in leaders enables a more true to historic progress feel and would, for many of us, be a very enjoyable feature. Particularly for those of us who really like the slowest game speeds and taking on the game as a true epic.
I also personally feel that the Developing Leaderheads and the trait levels you mentioned would play very well into this. It was actually the first step in the brackets of the project that RtS and I are hoping to move forward on.
As for memory, sure the Leader pic library will take up load space but very little in play ram use. And as this proceeds, at a point, it will be necessary to enable even more diversity for leaders thus a random leader system will be implemented. The larger the library of leader pics we have for this the better. Thus most leaders we could see in the game wouldn't even be pre-defined leaders and thus would not be taking up more load space. Just helps to have quite a few to draw upon for the building blocks is what it amounts to.
This also plays into the options we've discussed about having our leaders (and potential leaders that may be selected to lead in the future) represented on the board by actual units that have the potential for in-game mortality as well...
