Neil,
If you're using an electric pump, the one change that should be simple to do and would improve the system design is to move the pump location physically lower. I'm working from a very old memory here, but IIRC, the one real downside to the rotary's pump location is that it's at the top of the engine. That means that if for some reason you start losing coolant, the pump quickly loses its ability to move water. Again, if memory is correct, with the pump at the 'bottom' of the system, you can keep coolant flowing for a bit longer. It won't cure anything, but if you have a pressure leak it might keep coolant moving long enough to find a landing site.
I suppose it could have a slight benefit in the sense that it'll always have at least a little bit of pressure on the inlet, which could slightly reduce the risk of cavitation.
If my memory is defective, hopefully someone else will correct me.
Charlie