Maybe I am wrong, but I think you are under appreciating the difference between a star and a supporter. I don't believe that everyone who is a star can learn the mindset and skills need to thrive in a supporting role. Look at Iverson when he was asked to change his role. Similarly, what happened when Westbrook tried to change his game?
Obviously there are players who make the transition, like Grant Hill after the injuries or late stage Kareem, but it seems like most fail (we can see it now with Melo and Howard). So if a player has shown the ability to excel in a certain role, I value that more than the uncertainty of someone else growing into it.
When he was asked to be 3 & D against Kobe and Durant in the playoffs he hung just fine. Remember, I thought my most pressing need was a wing defender that could spread the floor. I again ask: Who in NBA history was a better wing defender that shot at least .35% from 3 (on reasonable volume)?
From your bench, Hill was not the level of defender and even when he was in a supporting role he couldn't hit the 3 at the same rate. Maybe you could argue Penny had the potential defensively, but his 3 ball was not consistently a threat at 31% for the career (although a good uptick at the end). However, even Penny was smaller, slighter, and had less reliable health than Battier. As for Petrovic, he never showed either interest or ability to be a defensive stopper (although I like him and had him top 5 on my board when you took him).
I accept that this pick is unpopular, but I think it is more interesting/revealing if everyone makes a team based on their own opinion, otherwise it just reflects group think and creates an echo chamber.
The reality is that we will never actually know, and even if it were possible to make this happen, the impact of the 8th player is probably going to be minimal... unless that player is Battier
