I honestly liked the movie, for a while though, i wouldnt even watch it cause i had heard that it had been changed a lot, but when I saw it I loved it and i will tell you why.
1) Peter's attitude- I disliked it at first, but found it an interesting addition because it sorta showed that he is human, not some perfect king who always did the right thing and never did anything brash, or stupid. It shows that he DID have a hard time with the fact that he left Narnia and may never get back. I also know for a fact that I would not (and already don't) like being treated like a kid (or at least a younger kid). And also, being the oldest in my family (sorta, i have 3 stepsisters) I know what it is like to have authority, and would hate to gain a lot of authority and then have it all taken away in an instant, and then, to top that, get back to where I had the authority, and find that I wouldn't hold that position for much longer because someone was taking my place.
2) Susan/Caspian romance- I thought it was a funny addition, it sorta added some lighter stuff to a darker movie, and was an interesting and clever addition, though it did not have to be there, especially because of Ramandu's Daughter and Caspian in the VDT, and it would be a little awkward for that to take place if Caspian had already fallen in love with Susan, but it looks like that will be okay from the trailers of the VDT..
3) The Castle Raid- Totally unnecessary, but added an awesome battle scene and developed Peter's pride and showed ,sort of, the reason why he was acting the way he was acting. It is one of my brothers favorite scenes.