It's not about what the stats would be at two different schools. It's about identifying traits, both physical and mental. I had pretty much avoided watching Alabama and had no expectations about Tua when I started evaluating him. If anything, my expectations were low. I was thinking 'probably a product of the talent around him'. But when I started watching him I was shocked by his killer instinct. As I said, he was the most aggressive QB I'd ever seen in college. When I'm watching a play develop from a QB perspective, I naturally identify where I would go with the ball. There are often safer choices, aggressive choices and of course bad choices. Tua more consistently went with the aggressive choice than any QB I'd ever watched. And he was usually right. He was very much the guy that would consistently go for the throat. That's the same way I would describe Jordan. Brady didn't show that on the field in college, but he showed that trait in the NFL. Nothing is definitive in evaluation. It's all projection. But you have clues that guide those projections whether they're physical or mental.
As for Brady coming out, I can say that I was high on him. Obviously, I didn't claim he would be a potential GOAT. But I did say I liked him as a starter. It was b/c I liked two of his traits that I find correlate highly with NFL success. Specifically, his feet and his accuracy.
As for Montana, Bill Walsh did say he could be elite. Walsh stated shortly after the draft (way before Montana ever played) that Montana had elite feet. Coincidentally, Montana was also considered a very accurate and very aggressive QB coming out. In fact, Montana was the guy who's game Tua reminded me the most of. IMO, other than being left handed, it was a better comp than Steve Young coming as he out relied more on his physical strength and running ability. Tua and Montana relied more on their pinpoint accuracy. Tua and Montana were in very similar offenses so you often saw them running the exact same plays so that comparison was easy. Montana was aggressive throwing into tight windows, but he didn't attack deep as often as Tua did. IMO they were both very ****y about being able to get their pass in anywhere.
A guy like Andre Ware never had much attraction to me. He had great stats, but that was largely due to the system. His exciting traits were about running ability and a big arm. That's what will get the fans excited about a prospect. But IMO footwork, consistent accuracy, processing speed are the things that get me excited about a QB prospect. But I always look at the mental traits as well. It's part of the evaluation and part of the projection.