I think the main difficulty the American military faced in Grenada was self-imposed. The mission was viewed more as a publicity campaign than as a military operation by some leaders. Instead of concentrating on a single unified military force, troops from a wide variety of units and even different services were all included so they would be “represented” in the invasion. And each unit used was reluctant to subsume itself to the command structure of other units.
But some good did come out of this. The command problems were so blatant that they prompted major reforms. It’s frightening to think what might have happened in the bigger wars in Panama, Iraq, or Afghanistan, if we were still facing the kind of confusion that existed in Grenada.