I've thought about this before, so here's the premise: If Cap, for some reason or another, had to leave the Avengers who do you think he should leave the leadership duties to and why?
My answer would be Namor. He's run his own kingdom and I think he would be absolutely honored if he was asked by Cap himself. They respect each other so I don't think Namor would let it go to his head. He's also hard-@$$ed enough that those under him would fall into line fairly quick and respect his leadership.