Adaptations to new coaching schemes are always major transitions.
But some coaches do a better job than do others in bringing things along. I have no idea how McV will do on this. But it matters.
I can imagine a really good coach having a plan for bringing the young QB along with doable stages of mastery. I also think it matters how capable the game plans are. And, I would raise the matter of team discipline, especially with regard to the receivers. It will make a big difference if our receivers are disciplined to run good routes and catch the ball. (Yes, I believe a lot of that is attributable to discipline instilled by coaches.)
If all of that goes positively, I can imagine Goff adjusting readily to the new system.
I can also imagine it all going negatively. I can especially imagine a young, rookie HC becoming impatient and trying to force feed ambitious game plans before the young QB and his unit are ready.
I just feel that a lot of this question of how Goff will adapt will stem from the coaching staff's performance. And of course from the performance of the OL, the receivers, etc.
In the end, if Goff does struggle, the temptation will be to put all the blame on him. Wise assessment, however, would look hard at the coaching staff.
