I said it a couple of weeks ago in a win, and it's even more apparent in this GB loss: JG's playcalling is bad. Actually, to be more specific, his playbook just barely suits some of his best personnel.
He's got a massive O-line, but prefers all kinds of slow-developing misdirections and draws instead of letting his line push guys around. So Hudson Houck, who likes those big guys and knows how to use them, doesn't get the plays called that favor his style of play.
He's got more possession-type receivers and RBs who can catch than he's got speed guys, but the quick slants, short outs and other pass plays that would take advantage of those possession guys (and set up his few speed guys better) are relatively rare. Except, of course, to Witten, which lets the defense roll coverage toward him and limit his effectiveness.
And he's got very selective amnesia: he forgets the running game entirely sometimes. Which is part of a vicious cycle: running plays don't work, putting the team in second- and third-and-long, which forces more passes, which disrupts the O-line's run play rhythm, which causes more running plays that don't work and hence more passes.
To repeat myself: if JG didn't have a QB as elusive and creative as Romo, he would have been fired already.