Georgia 2017
Miami 2017
Clemson 2018
Georgian 2019
Michigan 2019
And let's not forget the constant struggles the offense had from 2010-2016 under other coordinators.
My best guess is that Rees is far more qualified than you think. He's a real student of the game. This is his sixth year of coaching or analyzing. I would also guess that he studies numerous resources and has conversations with experts outside the program.
I admittedly have no knowledge of how Rees and Kelly work together during planning and games. But with Kelly being the headstrong coach appears to be, my other best guess is Rees is forced to work under certain parameters from which he cannot stray. And while I'm making wild speculations, I'm also guessing we'll see a radically different offensive philosophy vs. Alabama. Not in terms of overhauling the playbook, but in using the more aggressive and creative plays that are already in place.