Great post and I concur. As one who has worn that EP hat, I can say definitive Q-2, Q-3 situations happen. The were very few and far between in my experience and the squadrons I was in.
If I had any question about the validity of a rating less than Q-1, first, bad on me for not knowing my job, and second, I'd look at the instruction (reg in my day) for guidance ( and probably bounce off another EP or 2 ) before saying much of anything till the debrief. As for the debrief, regardless of the outcome, yes my duty was as an evaluator for the flight but I was also an IP as well. IMHO, every eval was also a chance to instruct if needed....of course in the debrief and not during the sortie.
Also, the concept of "extenuating or mitigating" circumstances is open to broad interpretation which I often did.....
In other words, a pilot would have to really prove they were deficient or completely unable prior to a 2 or 3 rating. I assume from the beginning they were qualified as a MQ pilot and as such deserved any appropriate benefit of doubt. Although I don't, everyone else has an off day.
Cheers,
Smokey