To be fair, Narnia 1 had a couple of cringeworthy elements (to mention just one, Father Christmas appearing) which put it into the “ridiculous stuff for kids” category.
Narnia 2 (in fact the fourth book), judging from the book at least, does not have those elements, so there’s probably less negative voting.
Also, the book is a favourite amongst readers (my personal fav is book 3, but then I’m weird) and has more scope for big battles.
Plus, seemingly, they have not been as painfully faithful to the very details of the book as in the first instalment…
Personally, I’m anticipating Narnia 2 about as much as The Dark Knight.