That might have been true in the day when defenses played stable fronts game in and game out. But now in the day of the amoeba fronts, complex delayed blitzes, and "roaming fronts", the skill level of the offensive front has had to grow to the point where it matches the sight reads that receivers often have to make.
You know, sometimes I wonder if sight reads for young receivers are almost counter productive because the read of the QB and the read of the receiver will ALWAYS misfire a certain percentage of the time even with Jules and Brady. I wonder if some offensive coach will "innovate" at some point and run just planned routes which would eliminate read errors and win on execution more than leverage.
Unitias to Berry - BOTH went to the HOF running patterns that everyone knew were coming, but simply out executed them.
I would think that giving rookies precise routes that they'd run regardless of the defense would increase their execution, make it more likely they will be where the QB expects them to be, and increase the likelihood that they could be more productive in their rookie year. Let them gradually evolve into receivers that can read the complex defenses that are more prevalent these days.
Its the old trade off that has always been there for football coaches. Execution vs potential schematic advantages. It looks so cool on the blackboard, but doesn't always look as good on the field
