This is a pretty silly argument. AD would literally be the best space-creator in the game (of recent memory, even) by adding a 3 to his arsenal. He would make the game even easier than he already makes it for his teammates.
Yet, somehow that is negated by what could be fewer offensive rebounds? What?! Sounds like dangler's assumption is he won't be a good enough shooter to warrant stepping out. In that case, fine -- makes no sense for him to be out there. I highly doubt he will be jacking 3s if he doesn't develop into an average 3 point shooter, though.