Of course every dropzone & skydiving aircraft operator have their own procedures for handling jump run without stalling. What jump run speeds, what engine & flap settings, how many jumpers outside the door at one time, sometimes how many jumpers allowed aft of a red line on the floor at once, all those sorts of things.
But sometimes people and dropzones are still learning, procedures and skills are not perfect, and so on.
In the King Air event that started this thread, I notice that they were jumping from 16000' AGL according to the description. (At a DZ by the sea, so it should be about 16k' ASL too) That's an unusually high altitude, when typical turbine jump operations are from 12k to 14k at the most. I'm guessing the extra altitude was unusual, so right at the start of a special event going to that altitude, what worked down lower didn't quite work out any more. Little way of finding out without actually doing it.
So no kidding they adjusted procedures for the next load!
While I'm not necessarily that critical of the pilot for stalling it, I was less impressed with that long recovery process. Admittedly pilots don't exactly practice spinning King Airs a lot but there are procedures for inadvertent stalls or spins.
(I have 4k jumps. I was a jumper inside a Caravan during a jump run stall, but that was relatively mild, with the pilot not exceeding 60 degrees of bank on recovery.)