My biggest problem with the zone is that the wing players sag way too far inside the 3 point line to try to prevent a post pass. As a result, they have to scramble about 10 feet (2 or 3 steps) to get out to the perimeter when the ball is swung their way. Tubby does this because he would rather give up a wing 3 than a corner or straight on 3 - based on percentages from each location.
So what ends up happening is that the wing perimeter shot is open to take, but also, since our guy has to jump out at the last second that 10 feet or so, it is really easy to pump fake and drive right around the guy jumping out on the wing. Then, other defenders have to step up to stop the ball penetration, and that's where we give up the open 3's off of the ball rotation.
I'd love to see the wing guys play about 5 feet further out to not make it a two-way go for the man on the wing. He could still take a quick shot (with less room than before), but with less room to cover it would also be much easier to stop the dribble penetration from the wing area.
Guys like Hummel, Moore, and Grant can shoot, but they can also dribble penetrate. I'd like to limit one of their options as much as possible. We don't really get beat very often in the paint anyway unless it is on dribble penetration, and Tubby is going to come with a double team regardless. I'd rather make it a little easier to get it into a post player that is going to get doubled anyway rather than the guys mentioned above unattended to shoot or drive.