will always be a factor insomuch as that’s how he views the game - his perspective stems from his play and performance as a QB.
Again, nothing personally against him, it’s that there is no proof he has that ability to be an in game play caller who is able to separate his playing days performance and lack of abilities (run, throw, and change plays, which all lacked as a QB) to putting the actual on field QB and offense in a good place.
On one hand you’re touting his ability to change plays at the line as QB as a solid reason his move to OC is a good thing - because that’s how he sees the game but on the other hand how he sees the game matching his ability on field is no reason to think that is how he will coach.
I’ve noted several times how Book’s game started to look like Rees’s game (which was awful when Rees was QB) making the same poor decisions and quite frankly derailing a talented offense. There is no reason I can see that as an OC this offense won’t sputter.
I hope I’m wrong on this and you’re right, but there just isn’t any real proof he’s the guy.