I have to agree. Caspian looks like a marshmallow here. There is more than one place in the movie where Drinian seems to have more authority than Caspian. Even so, Caspian was stronger than this throughout the rest of the movie. I would have loved to see his speech form the book. The one where he basically calls them all cowards and turns something they don't want to do into a privelege they don't want to be left out of. I like Ben Barnes and I think he could have done that bit of dialog very well.

The film mutiny scene is transposed from the book mutiny on Ramandu's Island to after the storm and before the landing on Goldwater Island. That is where it fits best, directly after Drinian interviews Caspian who tells him to ask Rhince whether they should give up or not.

I agree that up to that point Caspian had been reasonably decisive, despite Edmund's bossily arranging to take a party ashore at Narrowhaven and Drinian's having to remind everyone that the chain of command starts with Caspian. I have very mixed feelings about both the inclusion of this scene and its omission. If the scene is included it does very well explain much why Edmund would later be so contemptuous of Caspian on Goldwater Island. However, it might have caused the audience to see Caspian as more weak and uncertain than he was.

The trouble is that leaders are made, not born, and that someone like Caspian who has had only a bad example of leadership to take note of, might very well be uncertain about what his own father would have done, and also about how much latitude to give others, especially someone like Edmund who considers himself an equal.

I don't consider Caspian a marshmallow or the Marshmallow Puft man either.