I actually like Westhill the best of all the tracks in LFS. I wouldn't say it's missing ambiance any more than any other track in the game. It's just not a small-ish track in a fairly tiny, congested area like most of the others. I would actually say that if anything is missing it has nothing to do with the track.
The reason that you can feel all alone when playing LFS is that YOU ARE. There are no people milling around the pits and very few marshalls out on the track (none of which even do so much as turn their head or cross their arms). The people that are in the stands are all mute and like to sit very, very still. Nobody ever takes a picture or utters a word. There's no pit crew, no crew chief, nobody at all in your pit or talking in your ear. And you're all alone in the car too. Other than the sounds of the engine and tires (and now, diff/tranny) there's nothing else. No squeaky brakes, no pebbles hitting the wheelwells, no creaks from the dashboard.
While Westhill is very open with large runoffs, I certainly don't think that's the problem. The problem is that there really aren't any people around and there's no ambient noise. Imagine how much more alive LFS would feel with crowd noises, flag marshalls, pit crews, picture taking fans, people in the stands waving banners, etc.