Thank you for this.
I really would like to see Supes as the leader. It's nothing against the others. They all have leadership qualities. So, it's not that I don't want the others to lead or don't think they have what it takes, I just want to see superman take on that roll. It's just that, like you said, superman is a leader of kings. He's not the leader because he likes to boss people around. He's like the rock that people can break themselves against. He's steady, true and will never give up. He's well rounded and possess at least a touch of every quality a leader needs. He earns his position through inspiration of others.
It would be fair to say the JL doesn't have or doesn't need a defined leader, but I'd like to see them take on the challenge of writing a team that is balanced, but also has a defined leader. I think it could add to the arcs of each hero. For superman, we need to see him become that archetype of all that's good and fair, so that he's worthy of this leader of kings role. For the others, we need to see why they would willingly follow this alien into the abyss. Considering the strong personalities of people like batman and Wonder Woman, this has potential to be rather fascinating.