Having one "leader" that you roll all the executive functions or skills of power into, and who just does all those things while a bunch of "followers" do none of those things, is imbalanced and vulnerable.

If you have 1 leader, the government or counter-revolutionaries can easily assassinate, incapacitate, blackmail, bribe, or compromise that leader, and you can kiss your progress goodbye. If you have a council of the highest roles in different domains that are distributed amongst several people, it's much harder to compromise, the payoff is less, and a compromised figure is almost automatically replaced.