To elaborate of Wylla's comment, not only did Caspian and Peter not have a power struggle but also Peter did take full charge in the book. He automatically was recognized as the leader. Making them have a power struggle cheapened Caspian's character and his respect for Peter. The minute Peter was acknowledged as being Peter by the rest of the Narnians (Trumpkin excluded) he was automatically in charge. Caspian asked questions but he deferred to Peter because Peter was High King. Peter did not come to take Caspian's place, no, it was Peter's right and duty to command the efforts to put Caspian into his throne. Peter was High King over all Narnian Kings second only to Aslan. It was Peter's duty to see that all of his subjects, royalty or not got a fair shake. That makes it Peter's God-given duty to do everything in his power to put Caspian on his throne. He is not there to take Caspian's throne but Caspian is still his subject because Peter is THE High King.
YES!!! That is really good, Lava!! I agree with you totally!! Especially the last few sentences. Peter was High King, and Caspian would always be his subject, like Edmund stated in the VDT book when he says "I'm no subject of yours. If anything, its the other way round. You are subject to my brother, the HIGh King." Now, Ed did say that at Deathwater, but he was SPOT ON. No matter who Caspian was, Peter was higher than him, so they should not have had the power struggle. I loved when, in the book, Peter said "I haven't come to take your place, you know, but to put you into it." It was how MoviePeter should have started out behaving when he first got into Narnia. It seems like that is how he was acting, but he still had the "I want to be in control" sort of attitude. It was not as prominent as I originally believed though.
I agree with you that the power struggle cheapened Caspian, it sort of changed him almost more than Peter was changed, because in my opinion, Peter was provoked. When he and Caspian got into the fight when they first met eachother, Caspian attacked Peter, and he did have good reason to do so, but Peter was just responding to a threat, especially because his sister was right behind him and he had to protect her. Second, Caspian messed up the Castle Raid, and while I think Peter was not smart to not listen to Caspian when Caspian said that no one had taken the Castle, it was still Caspian's fault that it went wrong. Third, when they started arguing after the Raid, Peter provoked Caspian, but Caspian pulled his sword first. Again, Peter was responding to a threat. Finally, the witch almost coming back was Caspian's fault, yet again. He could have easily stopped the werewolf and hag from doing the whole sorcery thing, and in the book was willing to do so! In the movie, however, he wanted anything that would kill Miraz. He wanted revenge, and had a very selfish attitude because of that. Peter was trying to stop the White Witch from coming back, but stepped into a circle that he probably did not see. Because of Caspian's mistake, Peter almost falls himself! In all, I feel that Caspian provoked Peter and sort of caused some of Peter's mistakes.
But I still feel that the whole thing between Peter and Caspian was totally unnecessary. The Susan and Caspian thing sort of pointed to her change and eventual disbelief, which is why I liked that, sort of. I thought that was a little cheesy, but I love the humor it added to the movie, especially when watching the commentary.