All theory on photography is debatable. The decisive moment is no exception. For me it’s “a” decisive moment. There is more than one moment thinkable were elements in motion are in balance. All pictures need some balance in visual forces. It’s a stylistic choice. Therefor I can follow the thought that ‘the decisive moment’ has become a stylistic cliché. But clichés develop for a reason. Catching the decisive moment in for example wildlife photography creates beautiful pictures. For other types of photography other theories might be better suited.