I have unavoidably realized, through the viewing of several recent blockbusters, that simply having a character arc is not enough. Ending somewhere other than where you started is usually necessary, but on its own is insufficient.
A character must drive the story with their choices as an active participant in the unfolding narrative. Necessity for climactic change should not be thrust onto the character, but the result of their decisive action.
An inactive lead gives the work a feeling of disparateness where the plot exists on one plane, and the character on another. Character and plot should be inexorably bound together in their conception. They should feel absolutely mated and build causally toward a unified conclusion. Each should inform and feed the other.
Obviously, there are plots that will require a measure of passive motivation on the part of their protagonist, but this should always build to the eventual necessary action of the character, lest the plot or base concept become the true undefined protagonist in the eyes of the audience.
This is a dictum to be considered in large strokes, as depictions of wonder and surprise often live on the character's initial inability to react or lack of understanding. This is always most effectively used, however, as a means to an end. Working toward greater action that comes through understanding or awakening.