There's no doubt in my mind that Prince Caspian will eclipse LWW. First of all, like a few have said here...I've never been a big fan of the story in LWW. LWW's purpose is to introduce you to Narnia. So, now that we all know about this place we get to explore it abit more in PC.
The Pevensies start out immature and childlike in LWW...by the end of that movie we've fallen in love with all of them of course. PC basically takes the children (as a whole) at their peak and carries them through some adventures. If you're a pevensie-ite...then PC should be your favorite film. Instead of being children, they are kings and queens throughout PC.
Edmund and Peter are allowed to be more lordly throughout this story. As many have said, Reepicheep is introduced. There are alot of animated characters that they can choose to give larger roles in this film should they choose...just as they chose to do with Tumnus, the fox, and the Beavers in LWW.
I trust Adamson's instincts when it comes to animation and voice talent. I trust he'll deliver a wonderful Reepicheep. I think my only concern is the dwarves. I think I would rather him animate the dwarves with speaking parts, instead of giving us another Kiran-like performance. That dwarf was horrible in LWW.
They will obviously add some action to the front of the movie. Either by cutting back and forth between the Pevensies and the battle...or adding some other element of danger in the Pevensies path.
I definately look forward to Dawn Treader though. I think that should make the best movie of all of them if done right, as far as effects are concerned.