Blood players aren't actually natural leaders. Karkat and Kankri both failed to push their teams to do anything more than simply not kill each other, and that didn't last long either. Even the Signless's movement didn't actually get very far, if I recall correctly. They're good mediators and have a knack for fostering alliances, but that isn't the same as leading.

By that same token, Light players seem to be more skilled as strategists, with Vriska's planning and Rose's ability to see the most fortuitous path.

However, the Summoner managed to lead a rebellion strong enough to force the Condesce to banish adult trolls from Alternia, everyone seems pretty content to follow John despite his lack of social skills or even the ability to make a basic heroic speech, and Tavros recently managed to somehow show up with a whole army of ghosts in tow. I think the Breath players are the real leaders, as far as actually motivating people to follow them. Breath has been thought of as representing direction or motion in Sburb before, so maybe that extends to directing and/or moving others?