I don't know how any one of us can make final judgements as of yet on anyone or anything in the film yet, because we haven't seen it.
Trailers are not made with a lot of detail - as someone else said somewhere, its made up of a mish mash of clips from beginning, middle and end.
I had to watch this trailer a few times to make any sort of judgement because we are still having to read between the lines. That said, I really liked the trailer - and it isn't because I'm crazy with curiosity as to what it will really be like - and I can tell you that this trailer hasn't explained well, virtually anything.
I've put some thought into this - I don't know if any of my comments may assuage your concerns - but I hope this somehow helps or generates some more discussion.
1. Edmund: During the war, everyone was doing their bit for the war effort. Boys, especially looked forward to the day where they could see some action - and the day they were old enough to join up. Plenty of them lied about their ages. The passed four years of Ed's life in England were spent in wartime - I'm pretty sure with all the honour and duty he learned both in England but more especially in Narnia would compel him to action.
But let's hold up a second here. Edmund is more than just an English lad yearning for his chance to do his bit for England. He's also a King of Narnia - a King I might add who has seen his share of battles and he may feel as though he has something to contribute. And his reaction to being called "squirt" was only a frustratedly simple answer of "Squirt? I'm a King!"
Here lies the difference between Frustrated Ed and Peter Angst: Peter would have turned around and decked him. Ed simply scowled and walked away.
Now, I'm not saying that I am supporting a Peter angst in Ed - it would be overkill. I'm also not saying I disliked Peter's character arch in Prince Caspian at all - I fully advocated it - but I am just saying that Ed's reaction is different. Which leads me to my next comment:
2. Peter: Where is Movie Peter? Is he studying with the professor for his entrance exams to university? Hold on - wait up - isn't it still wartime? Peter, I believe, could be old enough to join the army at this point. If they have had Peter join the army, in explanation for his whereabouts instead of the professors - it would be historically accurate in our world. I can't imagine someone of Peter's character - who would chose to go to University instead of fighting in the war. I know that wouldn't be accurate with what is in the book, but I'm just saying - because they changed Peter's age in the movie...it would make more sense for having him join up.
And if he did join up - wouldn't that explain Edmund's behavior even more? It was rare that Ed and Pete did not go to battle together in Narnia (with of course the noted exception of Peter fighting giants, and Edmund's official tour of Calormene). I would imagine that if Peter joined up, Ed WOULD find it frustrating that he couldn't go to.
3. Peter and Susan: I was a little thrown by this as well. Not because they were there - I was expecting a cameo - but because it appears that they were wearing Narnian clothes and not English clothes. That's because I was hoping to see them in England in the movie, not particularly in Narnia, but I feel well assured by certain Narnian authorities that this is from one of the dream sequences/memories and is now not something that concerns me anymore.
4. Liliandil: I just found out Ramandu's Daughter's name - I am very excited firstly, about her name, and I think she's going to be very very lovely. I also like the concept of her showing up in other parts of the movie before they actually meet her on the island. However, I am not a fan of the way she is glowing. I would imagine she would sparkle, but the glow is terrible. It looks like bad 80's special effects. That said - if she can fly like that up to the heavens - how on earth is the Green Witch going to kill her in Silver Chair?
5. Caspian and Eustace: Not very much of Caspian, obviously, but we'll see lots of him in the movie. Eustace, on the other hand, they're probably keeping a secret to lure us into theatres because we're all curious about him
Same goes for Dragon Eustace...I have a feeling its because it's going to be the best part of the movie...
6. Coriakin, his house and the Dufflepuds look really good. And Lucy is wonderful and grown up
Movies are never exactly as the book is. I, for one enjoy all the enhancements they give me - CS Lewis wrote in subtleties - meaning that he left a lot of room for additions and interpretations. I've been a writer since I was a girl - and I've always been fascinated how he can describe something in a couple words that others would use a whole paragraph for.
He once received a letter from a young fan asking him if he were going to write anymore stories of Narnia. He wrote back and said no, but that there were a lot of adventures that happened in Narnia, and that we (the fans, the young writers) ought to write about them. I think he'd love the fullness of these movies.