I don't think this is true. Cuz gets frusterated on the court sometimes but so did every other great player. Being a leader in the locker room requires 2 things. 1) you have to be a great player. Nobody cares what a scrub says. 2) you have to be intelligent and well spoken. Cuz is both of those things. I really think he can lead a team. Will he be better at in 10 years? Of course.
In no way did I suggest he would never be a good leader. Just that with his current level of maturity his emotions could cause problems with the rest of the team.