The Hero must prove himself many times while on adventure A hero just can't claim he's a hero and assume his position, now can he? The hero must prove to himself and others that he is the true hero.
Luke faces Darth in battle several times during the Star Wars trilogy. These battles, along with other services Luke provides for the Rebellion, his training with Yoda, and his personal maturing are part of the trials he must successfully pass through to become the hero.
Arthur's success in battle, just like Wallace's, is part of the proof of his heroic status. Leadership and courage allow the hero to overcome obstacles that lesser men could not. That's the hero for ya'!
Simba, like Luke, is immature at first and unable to be the hero he will eventually become. However, once Simba realizes Scar must be removed and Simba is the only one who can do it, Simba assumes his proper role as the hero and saves the land from the evil Scar. Hmmmmm, that -does- sound just like Luke, doesn't it?