It sounds like you have considered all the angles. I've just seen situations where management was blinded by the "hero programmer". However, with the perspect

It sounds like you have considered all the angles. I've just seen situations where management was blinded by the "hero programmer". However, with the perspective of the third member, it sounds like Rob is the weakest link (BTW, someone has to be the weakest). If he really is messing up your team's mojo, then either work towards the goal of "Making Rob Better", or make a business decision and let Rob go.