Thanks for the great detailed response once again. I'll have to wait until some testing has been done before I do any changes, but a few comments on what you posted in your screens:
1: Good idea - I probably will.
2: I might do that, it's just that it would mean having to demolish a detail area.

I definitely see the need for it, though.
3: I actually thought of doing that, but I left it like that because I didn't want too many side paths and stuff. We'll see.
4: Hmm... Yeah, I was unsure about the side path, but I want it there. I want spies to be able to get up there easily to sap sentries, but I might make a little ledge like you suggested and put some "crate stairs" there.
5: Maybe. I think it makes sense to be able to cap there as well. I guess I could (re)move the health and ammo, though.
6: Dunno, common problem with shadows, I think.
7: It's a window.

8: I suppose I should add a fence there, yeah.