The biggest problem with being on the ground in a mission is the fact that everything—military and civilian—is controlled by the civilian side through the UN headquarters and answers to the UN.
In one of my favourite stories—and I can't even tell you what mission it was—a military commander wanted to do a helicopter operation and planned to get the orders from someone, and then when it came time to launch, he said that the petrol wasn't permitted, allowed, signed off, or authorized by the chief administrative officer of the mission, so the helicopter operation didn't go.
The biggest problem is the command and control, and that's where Denis in the MFO had the wonderful arrangement where he controlled both and was able to do anything.