Okay, so these clowns aren't going to be real with you.
The truth is there's no telling how much Koetter had to do with actually being allowed to manipulate things. His play design is solid, however if the fact that his playcalling was inconsistent at best is a bad sign. If it in fact was his desire to run the Falcons offense the way it was and he wasn't forced by another power within the Front Office.
The Falcons offense sucked outside of the no huddle, and if he was the reason the Falcons continued to use Steven Jackson until injury removed that option, then he's a complete bafoon.
The Falcons offense was at it's best when Matt Ryan was adapting the plays at the LoS. That would indicate to me good design but lack of understanding of play calling. If you do go with Winston, then you could be in for some seriously wicked offense seeing Winston's level of understanding.