Absolutely, you make a good point I didn't clarify. I wouldn't discount the amount of people that stand behind and influence a leader. My example of ubermensch is aiding to the "Jesus"-esc image we give to great leaders.
OP asked what makes a great leader; my interpretation is that good leader is the strongest in terms of decision making and management. Sometimes we don't see all the inner workings of leader, we are just given an image.
Let's look at a different concept, in business called Peter's Principle. Everyone rises to a level of incompetence. In term's of CS, imagine a MG2 playing with a four stack of Novas. The MG2 may have been the top dog in MG2 and lower ranks. They know more plays, more lineups, more everything. Now put that MG2 in a four stack of GE's. Guess what? You've just played yourself, you're now at a new level of incompetence. That's Peter's Principle.
The higher on the totem pole, the closer you are to "leadership".