My short answer is that it works. You have before you someone who has been commanding on two occasions, and I presided over summary trials. From a chain of command perspective, a military perspective, it's the best system there is: there are no arguments, no rules of evidence, and you don't have to be trained for it. It's very efficient—in walks the individual, and out walks somebody who's been sentenced. That's it.
But that was then. We're not at war now. This is not the 1900s, it's the 2000s. We've progressed. We didn't have a charter then; we do now. Our soldiers are more educated, more sophisticated, and they demand to be treated equally with civilians, their brothers, in civilian court.