I dont think you really understood my question, napalm. I was distinguishing the movement (the motion your body makes) from the load the different exercises place on your muscles.
But yeah, the good morning is such a great lift, and between that and RDL it definitely provides more of a benefit to squats and DLs than RDLs do. Having strong legs is easy - having a tough lower back and a tougher upper back is a little harder. But both do really drill the hip thrusting well.
Also, I think Rodja and Zir have pretty much summed up what's important in the GM. Not too technical, huh?