Is it possible that anyone is surprised by this? I expect it to be as onerous as possible.
Nope not suprised at all. DC already had this law pre-Heller, and chose not to issue ANY permits for many years. It won't take a rocket scientist to figure out they're just going to do the same thing, maybe they'll issue to a few cronies just for show.
The question is how this plays out. From Scullin's opinion, this won't fly with him. But perhaps DC is hoping to carry its new may issue to the DC Circuit, get a sympathetic court (with our nemesis Judge Henderson) who will then follow Kachalsky, Woollard, and Drake and uphold it.