I realize this may sound crazy, but I think if you are going to redo M2, then you should fix the water room with the r_speeds through the roof. I do have an idea how to do this too:
Take the basic: --------------
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This is the donut wall/hallway thing, I am sure you are familiar. But what if u rotated this on the X (i think) axis to make it like a wall in the middle of two floors. I say make a 1.5 floor that does not completely cover up the water view, but does let u see alot of It, but at the same time makes another landing to run around on and on the sides, can drop down into the "water" room.
Tell me if this is uber confusing, or what, but IT looks great in my head, and most likely would work, so yea. Use the idea if you should want to.
-Cusoman