The irony being that Harry P's offense has a lot of freedom, in terms of versatility of players, shot selection, etc.
Running set plays is not the same as an offense not having freedom. For example, Shoni Schimmel and Angel McCoughtry had longer leashes (especially in their respective senior seasons) to dictate the offense, rather than going through set plays, because they were the creators (for themselves and others). Additionally, inverting the guards/forwards in terms of expected shot selection, etc., is part of offensive freedom.
As an example, at Duke, McCallie wants guard to shoot from the outside and post players to be inside (with a post player only venturing out of the paint in a bigger zone on defense, by being placed at the foul line and extended beyond). Walz uses the existing skills his players have and develop their versatility, especially with his forwards (the 6-1/6-2 types I mentioned in my original post in this thread). He takes advantages of mismatches and forces teams to adjust to him. This is why Duke is a much easier team to defend for opposing coaches because there is not the offensive variety or the "unexpected" for which they have to prepare.
Re-reading your post, I see what you are saying. Walz is dictating a good amount, but he gives his players the freedom to maximize their skills, rather than delineating their roles solely based on designated position.