Anyone ever eliminate the prop valve?

Yes, this thing is two separate functional devices "in one box." In the drawing, the piston on the left side (of your device) is the shuttle which actuates the warning switch, and you don't want to remove that, as it would then CONNECT the front/ rear hydraulic paths

The "bottom right" section of the valve, in the drawing of your device, is the proportioning section. If you look at a (for example) 67 all drum warning switch (pictured below) with NO proportioning valve, you can see the "switch only" and how it works, and that it is essentially, "half" of the newer combination switch/ prop valve