One of the best things that came out of Murray's workout was the claim by people there that his delivery was quick. If you watch highlights of the guy he always had a hitch, not as bad as some guys but he would drop the ball down a bit and then come back up and throw it. That led to some plays where even with his extremely strong arm, wide open Wr's would be slowing up and waiting on the ball at OU. From what I read of his pro day, that was not the case there he had a quick release with no apparent hitch.
I also agree with what Krang said, there's a difference between running QB's and elusive QBs. Aaron Rodgers is elusive, Russell Wilson is elusive, Colin K and Grifin were running QB's. The problem with running QB's is they get hit by NFL size defenders and they get hurt, elusive QB's buy time to get the ball downfield, or run for a few yards and then go down or step out of bounds. For years I've been complaining Wilson drives me nuts, but what drives me nuts is we never get to unload on him. We sack him but they are never big hits, and when he runs, he steps out or flips the ball forward to avoid the hit. If you watch Murray that's one of the things that immediately is obvious, he doesnt' get hit that much. Yes they had a good OL but he just doesn't take big hits he finds a way to avoid them.
My biggest concern with him has always just been lack of experience.