I do like the concept- utilizing pre-existing structures makes a lot of sense. Lately I've been running around in the campaign and then comparing it to some of the multiplayer maps, and I'm almost certain Gearbox at least, if not Bungie, did the same thing in reverse.

Looking at those screenshots I think we should take into account where the player is going to be. Are we going to run out of the structure with the MC and cross the half-bridge, never going down onto the wide plain? If so, then you wouldn't have to focus as much on it, maybe some rock scenery, etc. That being said, if we do end up going down there, and that smaller structure isn't just for show, then I agree that it is too sparsely built. I'd recommend another ridge, or some hills.

Oh, and just to be thorough, that light shader needs its framebuffer blend function to be set to "add", fixing the alpha.

And 23/7 bsps? Kudos to you!