I don't think rawbots still uses the default unity physics. IIRC, it got replaced with the bullet physics engine.
I've not noticed anything gyroscopic happening with spinning masses before, but it could be interesting if it does work.
I built a leg on a test platform, and came up with a few observations:
>The foot must have matched the bots speed before it touches the ground, and must be lifted before the leg finishes the power stroke.
>Grenades make poor feet, and continuums work ok but aren't round.
>Small wheels make good feet, but are quite big
>The fast leg movements should use an open-loop controller, with a slow closed-loop system to tune the settings of the fast loop
>Synchronising multiple legs could be tricky, especially when reversing/steering.