This is a concept I have investigated myself so it would be great to see it put into action!

You are more likely to catch the wedge on a join in the floor than on the edge of the pit IMO, o just put all small chamfer on the edge so no matter which way its going its going to ride over any bumps.

My idea has a small ~1.5kg reversible drum (this was for a FW) in the middle of the pivoting section so that I would always have a weapon no matter which way up I was, but just having it as a powerful passive slambot would be good too.

If you got under someone you could move the pivoting unit down, lifting the front of the robot up and getting your opponent properly off the ground!