I'm so late to the discussion that I'm only going to suggest one really fucking important thing: in considering coordination, leadership, and team work in cRPG I implore you to draw insight from any and all of your experiences with other games in which multiple people have participated. This applies mainly to video games, however I'm sure an adequate number of "good ideas" can be found in the guise of those other competitive games we've played through out our lives: tag on the school playground, board games with friends (if you have any), sports, etc. While cRPG is special, and is the focus of our discussion, let us remember that it is at it's very core a game.
How were leader's picked for the school yard games we all vaguely remember participating in? Normally popular consent, no? Though I remember occasions when we would rotate leaders so that everyone had a turn to take charge in capture the flag--fair, but there was lots of sucking. In the Empires mod for HL2 leaders are voted for at the beginning of each round, though the coordination is made possible by a clever squad system.
But who needs leaders when the simplest of forms of coordination is possible, such as when myself and my friends play basketball (I suck). There there are no leaders, only basic commands like "cover that fucker!", and spontaneous coordination whereby I simply know to go for the rebound because I'm the closest one, and no one's covering me. The same thing happens when a pikeman takes a moment to look around, and seeing that the rear of his team's gaggle-fuck is exposed to enemy cavalry, moves to the back of the "formation". In this, heed Joker's advice when he notes the misconception many have about team work, that "[it's] like playing a small...Napoleon Bonaparte, sitting over a map and discussing about flanks and reinforcements". It can be much subtler.
First and foremost I suggest that there be official ventrilo/TS servers--because coordination is greatly facilitated by communication. This includes verbal communication, though there are uses for non-verbal (banners, flags, chat, etc) shit.