Maybe she needs her trident. Or maybe she needs Gentiana, who was nowhere to be seen or even mentioned in the movie, kinda weird considering Luna and her have been friends/allies/whatever ever since she was 17 or so (Brotherhood).
Anyways, I very much disliked her character in the movie. But I'm very positive that the game is not going to portray her in the same manner, mainly due to the difference of writers, the fact that it's a game (they encourage battle, especially since she has a weapon at least) and the situation she's going to be in. Although that wouldn't mean she's going to be a great character, mind you; I've liked what we've seen of her in-game, though, especially with her newer in-game model: she doesn't look that much like a plastic doll anymore and is much more natural.
Same goes for Ravus: he was featured for what? 3 or 4 short scenes? And then he's never seen again. I expect him fullfilling a better or at least meatier and not as petty role in the game. He's got the design, so let's see if he uses it to be a good antagonist, main villain or whatever he's written as.