I think Alves has the capabilities as well. He could be the one that wakes up everyone but he needs some more seasons with Barça before he can pull that off.
I don't see Messi, Xavi or Iniesta shouting at their team mates like a captain has to do. So I agree with Janosik. Only thing with busquets: he always falls like a girl when someone hits him. That's not the way to portray leadership (same problem for Alves actually). A leader should be one of the hardest, setting examples for the rest and let them know that his spirit is the example.
A good example of a leader is Gattuso. Resembles Puyol.