I know of some people who teach evolution but do not mention Stephen Jay Gould or punctuated equilibrium. They know about it, but they are of the old school and can't accept it. So there's a lot of politics involved in this, even among themselves. There are two major camps on this explosion business. One is the good old Darwinian explanation that we simply haven't found the intermediates.
Fossils are hard to form in the first place.
But a lot of younger scientists are turning to new ideas. The first idea put out was the oxygen theory. They say that maybe in Cambrian times the oxygen level in the atmosphere and in the oceans suddenly arose to a critical level which could support larger-sized animals. That theory is pretty much shut down because there should be geological evidence for a sudden increase in oxygen. There are other theories, too, like that of Berkeley professor James Valentine.