By having a leader that can be chosen by more than one civilization and a leader that switches randomly his traits, I think we could open the game up for some more unique ideas.
My idea would be a leader that starts out with no trait except adaptive, but that can choose two traits when adaptive triggers (If you want to make him stronger he gets charismatic as his fixed trait after turn 96, another trait after turn 196 and his last trait after turn 296) Flavorwise he could be a shapeshifter that has infiltrated a civilization or works with it together (I'm especially thinking of the Sidar, which at this point only have one leader and he would fit their flavor). So if you chose him you could either select a random civilization or the Sidar.
But why should you limit this to traits? This leader could also have the choice if he wants to be a man or a woman. If you linked to him a relation bonus to the opposite sex it would even have a game meaning. At the beginning (until you choose his traits and his sex) his picture should look quite indefinite, unimpressive and androgynous, but after you have chosen his sex and his traits he should have the picture of an incredibly beautiful man or woman (because he has managed to adept himself to the human ideal of beauty).
My idea would be a leader that starts out with no trait except adaptive, but that can choose two traits when adaptive triggers (If you want to make him stronger he gets charismatic as his fixed trait after turn 96, another trait after turn 196 and his last trait after turn 296) Flavorwise he could be a shapeshifter that has infiltrated a civilization or works with it together (I'm especially thinking of the Sidar, which at this point only have one leader and he would fit their flavor). So if you chose him you could either select a random civilization or the Sidar.
But why should you limit this to traits? This leader could also have the choice if he wants to be a man or a woman. If you linked to him a relation bonus to the opposite sex it would even have a game meaning. At the beginning (until you choose his traits and his sex) his picture should look quite indefinite, unimpressive and androgynous, but after you have chosen his sex and his traits he should have the picture of an incredibly beautiful man or woman (because he has managed to adept himself to the human ideal of beauty).