Ya, Goff was a disaster in empty. Slow release, inaccurate, frequently seemed to just freeze. The Miami game is etched in my brain...that was so painful watching goff attempt to be a qb in that game.
Empty for Stafford and other elite Qbs is a way to force defenses to show their hand. More importantly there are not that many variations of coverage versus empty that a defense can employ--especially versus four WRs to one side which the Rams have done alot of this year.
So, McVay and Stafford study a defense's tendencies--how do the defend empty and gameplan counters. Stafford is so good at understanding what the defense is doing, prioritizing his options, and moving from read to read that with his quick release and super accuracy he excels at empty.
I think empty will be key versus Arizona. Both for the offense and the defense.