Well the title did not let me guess the subject (as usual I like that ;) ).
I saw the film about two months ago, and well I must also say it is really something a lot different of Narnia. I think the whole change was made under pressure of the Disney studios, who high-handedly impose their long experience of "succeeding stories". The changes of hair color and the father's nature do really help the producers to disguise the film as the common Hollywood blockbuster that it certainly is not.
See ya !