Good write-up! I would only partly disagree with your "Even back when the last two DLCs didn't do this" in the 5th paragraph. As they did make it so that if you hadn't "purchased" the DLC, then you were not always allowed to do the Weekly Heroic, or the Nightfall. You weren't completely locked out of all of them, but enough times that everyone should have realized (at that time) what they were capable of doing to everyone.