Democracy not being a road to success is a highly debatable topic. Let me start my post by asking a hypothetical.
First, what is success? Is it being rank one? In that regard, if this guide is presented as a means to make leaders successful, it is targeting a very small audience (there are currently 35 open worlds), and each world can only have one number 1 tribe.
Moving on, I think its clear that a dictatorship can be successful (the term "success" being used loosely here). It's also been shown in the past to not be successful. The same can go for democracies. Obviously, certain techniques are going to work with different types of people, and fail with others.
You are right that communication is necessary in any tribe, regardless of leadership style. You are also correct that a leader in a dictatorship can communicate with the rest of the players in the tribe, and treat them on the same level. However, notice how I italicized treat. In a perfect dictatorship, there is one guy calling all of the shots. While he can communicate with others, the ultimate decision is his. Let's call this the "far-left" in terms of leadership style. On the "far-right", you have it's exact opposite: the perfect democracy, in which event every person has exactly equal voice in the decisions made by the tribe as a whole. No one person makes the final decision. In between the far-left and the far-right, you have tribes with leadership councils, etc etc.
Assuming all styles of tribe leadership were equally effective in terms of war coordination, diplomacy, etc etc, which would provide the best community atmosphere? Which style would provide an atmosphere where players would want to stay around longer? It is my argument that all things held constant, a democracy would provide a more fun environment, so given the choice between a perfect dictatorship and a perfect democracy, I would choose the latter.
Admittedly, a democracy will be harder to pull off due to it needing a higher player compatibility. Different types of players will thrive in a well-oiled democracy then those in a dictatorship. Making the assumption that a mass-tribe democracy is a waste of time based on this fact however, in my mind, is a large stretch.
We can all play the "history has taught us game". I can point to tons of city-states, countries, and empires that have all failed under the regime of a dictator. If you'd notice, many countries in the world base their governments on a representative democracy because of the fact that a true democracy just wouldn't work due to logistics (ie, extremely high populations make it un-feasible to operate effectively).
Tribal Wars on the other hand typically has smaller tribe populations then countries have civilian populations. Essentially, the smaller the population limit, the more feasible a democracy becomes.
Now, based on all of this, I can only agree with Inuyuki's original assessment that this focuses on a certain niche. That doesn't mean its necessarily bad. While an ok enough read, different people are going to agree to it to varying degrees, and you have to expect that when presenting a Guide to Leading that only focuses on one dimension of it.
