Do you want your story to bring your audience to a point of change or to reinforce its current view? Oddly enough, choosing a steadfast Main Character may bring an audience to change and choosing a change character may influence the audience to remain steadfast. Why? It depends upon whether or not your audience shares the Main Character’s point of view to begin with.
Suppose your audience and your Main Character do NOT agree in attitudes about the central issue of the story. Even so, the audience will still identify with the Main Character because he represents the audience’s position in the story. So, if the Main Character grows in resolve to remain steadfast and succeeds, then the message to your audience is, “Change and adopt the Main Character’s view if you wish to succeed in similar situations.”
Clearly, since either change or steadfast can lead to either success or failure in a story, when you factor in where the audience stands a great number of different kinds of audience impact can be created by your choice.