This is, of course, a matter of opinion. Different people have different views about the relative utilities of hierarchy and egalitarianism. For example, the leaders of the Chinese government would be likely to say that it is important to have hierarchy. As another example, military leaders would say that it is impossible to have a good military without having a hierarchy. By contrast, most civilian leaders in the United States would say that egalitarianism is superior. Let us look at some arguments for each side.
People who are in favor of hierarchy would generally say that it is better for humanity because it allows things to get done more efficiently. When you have a hierarchy, you are more likely to accomplish the things you are trying to do. The people who are higher in the hierarchy are able to tell the people lower down in the hierarchy what to do. They can simply give orders and expect the orders to be followed. They do not have to spend time persuading people to do things. This makes things much more efficient. There are many people who would say that this is very important.
On the other hand, people who are in favor of egalitarianism would say that it is better because it allows people to enjoy their basic rights as human beings. They would say that efficiency is not really all that important. What is more important is that people should be able to enjoy their human rights without being told what to do all the time. This is what many people value about democracies like the one we have in the United States. In an egalitarian society, people are free to determine their own destinies to a greater degree. This may be less efficient, but it does more to honor the humanity of the people in the society.
Thus, I would say that there are arguments for each side. Hierarchies are good when efficiency is needed, but egalitarianism does more to protect human rights and dignity.
I believe hierarchy best serves humanity because it is not as harmful. Yes, having a hierarchy would result in inequality and wider social, economic, and all kinds of gaps. But these gaps are nothing new to us. We have hierarchies already that we experience every day. Although egalitarianism can result in each person having their own basic rights and freedom, it can also result in danger. America started from the idea of freedom. And since its establishment, the emphasis on freedom of choice has only been growing. Conflicts have become much more complicated -- maybe even insolvable. And people are only getting more and more extreme. Because of this, some people, not all, have been making bad decisions out of their freedom and harming people around them as an effect. For example, people who choose to smoke marijuana. It's allowed now in some states but if you choose to do it and then go behind the wheel, you're endangering everyone around you on the streets, especially if you're high. That may be an extreme case but it happens every day and it's become a statistic now. There are of course much smaller decisions people make in their daily lives, but each decision holds so much power and can influence the lives of others, good or bad. It's hard to trust a whole nation or world of people -- that they'll make wise decisions so others won't be harmed. Therefore, I'm not a huge fan of egalitarianism. To keep the world flowing more efficiently and more systematically, I would suggest that humanity would be better served by having a hierarchy. It doesn't have to be a hierarchy where the upper classes would look down on the lower classes and hold arrogance. I'm talking about a system where we just have different ranks and people have different jobs/tasks/duties to society. Let each person take their different job and do it well. That way, there's more order in the world.
I believe having a hierarchy is better for humanity. Studies have shown that egalitarianism breeds an abundance of choice and freedom, which is, paradoxically, harmful to society. Having more choices actually causes a negative impact on humanity. In contrast, a hierarchy will allow everyone to know their place in society, and it will allow society to run more smoothly with set rules and regulations.