Ok, I'm sure everyone is familiar with the area pictured. I was thinking about it recently and have a suggestion to make it more interesting.
1. We extend the 3d floor platform into the base, so that there is a ledge inside as well. The purple area is where it could be extended. As you can see there is a void just to the south of the ledge that can be made into a secret area. Could put a stash of useful items here.
2. A ladder is added at this side leading up, so that it is semi-hidden but not too hard to find.
3. Here is a 3d view of what I am trying to describe. The green bits are the alcoves or doorways that the player can move through. Putting chaingunners or rifleguys up here to snipe and ambush the player could be effective.
4. The green hatched area is of course cut away as there is now a 3d floor ledge here. The green hatched area could have a midtexture grating too.
This is just a suggestion for anyone if they are willing to implement it later in stage 2.