This could have worked...

Seriously, on paper, this sounds like an interesting story. An invasion of the body snatchers, and then one of the snatchers befriends her host and learns what it means to be human. Also, the idea of two beings inhabiting one body sounds pretty cool. There's even a few decent scenes. The scene where Wanderer enters the med lab and finds her dead kin is particularly chilling.

So what's the problem? Well, first of all, the movie moves at a snail's pace and is a chore to watch. An alien invasion movie should be much more interesting than that. Second, antagonize the Souls. The Souls are supposed to be the villains, and you can tell by the way they've created a utopia. Seriously, make them more parasitic...like the pod people. And finally, it's Stephanie Meyer. As such, the action and sci-fi elements get pushed aside to make room for what's really important: tween porn and romantic subplot. >:X Just what we want from our sci-fi movies.

Fix any of these elements, and I guarantee you, The Host would've been a much better movie.

Brother Maynard, bring forth the holy hand grenade!