[The Saucepan Man]

It seems to me that there is a book-based justification for film Aragorn's reluctance. During the period following Gandalf's fall in Moria, when he has the leadership of the Fellowship thrust on himself, he frequently and increasingly questions his own abilities. This reaches a low point at Parth Galen, in particular with Boromir's death, when he seems in a state of utter despair and laments that all his decisions seem to have gone awry. Yet, with a firm objective (the liberation of Merry and Pippin) which requires him to use those of his abilities which he trusts the most, his tracking skills, he gains steadily in confidence, ultimately to the point where he proves himself a worthy King.

In the book, he has to prove himself both to himself and others. The films simply emphasised and stretched out this aspect of his development as a character. And I think that it works well in the context of the films.