with other qbs id be a bit careful about that because having the ability to fundamentally re-work your mechanics the way lamar did is unprecedented - the one thing typically scouts say doesnt really change from college to the NFL is accuracy and yet lamar improved by almost 10 points (completion %)
to expect that from other qbs is not realistic - that being said i do agree that coachability is important but overall id just emphasise all the mental aspects first over the physical - can they read defences, can they do it at speed, can they identify deception, can they make the right read, do they throw with anticipation, do they have good pocket poise, how quick is their release... then move on to things like how strong is their arm, how strong is their arm when out of phase etc. etc.