The offensive line wasn't the issue that game. It was the defense. That was clear as day. If there is an area that needs immediate attention, it's the defensive side.
I agree that the defensive line is the biggest area of weakness.
That said, the inability of the defensive line to give Brady the time he needed prevented the come-back attempt at the end of that game from even getting off the ground. Maybe I'm biased by that being one of the last and most important plays of the game, but they couldn't give Brady time when he needed it most.
That wouldn't have mattered if the defense had been able to stop a nosebleed or get any pressure on Foles, though. The defense, especially the line, is the biggest priority.
But I just think anything less than excellent is not enough when it comes to the offensive line. Not when you have a 40+ year old quarterback.