Hi all, just my two cents about the lack of choice in the WP scene, sorry if this is retreading old ground...
I don't feel the lack of a true alternate path (you can start shooting, but you can't go down the ladder) cheapens the scene. It has a solid justification (narratively and for the sake of realism), that sometimes in real life the only 'choices' you have are bad ones, which is clearly lampshaded by Walker in that scene. And quite simply, consider the option that some people are clamouring for: that there be an option to engage in a ground war against the entire force, miraculously survive (though still plausible under videogame rules), 'liberate' the refugees...where would the story go from there? Walker wouldn't have crossed the moral event horizon, there'd be no reason to feel any guilt about what you'd done, you'd go on playing the same 'America saves the day, protagonist always takes the good-guy option, keeps his moral integrity intact'-game we've seen countless times. You'd likely hate it even more.
I think the problem is that if the developers scripted a route from beginning to end that was persistently 'paragon', most players simply couldn't help themselves, and would constantly make the 'right' decisions. In non-interactive media, some of the best stories involve our protagonists doing bad, bad things that change them. But with the benefit of walkthroughs and quickloads, I think most people would simply take the easy way out. Despite the murder-crazy gamer stereotype, I think most people find it difficult to make the 'evil choice' in games that offer them, at least for their first playthrough, even if it's the more interesting path narratively. So in effect, most people on finding out they'd accidentally torched a refugee camp, would reload their last save, take the narratively bland path and save-the-day, and miss out on Walker undergoing the transformation that makes his arc so much more interesting than other video game protagonists. So the developers chose to remove the choice completely, so they could tell the story we couldn't be trusted to pick ourselves.