It would cause some shifts.
In order to be viable candidates, Republicans would have to move more to the middle of the road as opposed to the Tea Baggers and Radical Right. Scharzenegger got elected in a Blue State so don't give me that crap about it leaving out other parties. That's bullshit and you know it. We might actually have viable government again, if ALL states went to this system because the two parties might actually work TOGETHER rather than carping and playing one-up-man-ship and just generally play their "screw everyone including the voters game" rather than govern.