Yes, we're told that they're in command of various things, but we never see them actually commanding. The most Luke does is order his wingman to cover him. He doesn't make any major tactical or strategic decisions, doesn't come up with a plan of battle or anything. Likewise with Han on Endor. When you compare them to the way Kirk and Picard are portrayed in the Star Trek movies, or Gandalf and Aragorn in Lord of the Rings, it's really hard to take seriously any claims that they're leaders, let alone great ones. They're just individualist heroes who occasionally get red shirts to accompany them on missions.