Ty Buchner (spelling?) came in with Coach Rees and a lot of folks were saying Ty would obviously be the starter since he knew Rees' system. Didn't happen.
My money's on Milroe. (Assuming he stays, of course...)
well, those folks didn't understand how Saban worked. It was not Rees' system. It was the Alabama system, with the plays called by Rees. We didn't change the playbook, or any terminology when Rees came in. He likely added a wrinkle here or there, but it was not a system change. Buchner actually had more to learn coming in than Milroe or Simpson so had zero advantage.
What we have in front of us is a complete system change. I'm sure the guys in the QB room have the playbook now and access to film, etc to watch, but Mack has a pretty significant headstart in being able to know the offense.

