"Each of these aspects of a QB’s performance is indicative of their true skill and is less affected by circumstances and luck."
I have a big problem with this. Performance when under pressure and outside the pocket is more affected by circumstances and luck and performance when protection is clean is more meaningful? You brought up Brady and he would be a great example. He was throwing balls away, daring officials to make the grounding call, when he was facing pressure. Being unwilling to take a hit to make a play is luck or "circumstances?" Some of these QBs can't escape pressure and making plays on the move and outside the pocket is not even an option for them. It's a club that is not in their bag. I don't know how you can evaluate some QBs for parts of their game that do not exist for many of them.
Most all NFL starting caliber QBs perform well when not pressured or else they would not have the job. So how could that be any meaningful way to evaluate their performances? This author used their ordinal ranks after only two games to to say that Josh was middle of the pack in the "meaningful" measures: clean pocket QBR, no play action, completion% over expected and poor throw % even though the clean pocket QBR is a solid 79 and the bad throw % is a stellar 16% and SIS has him 4th in on target throw %.