Even if Yoshida and the development team had a certain play style in mind for each class/job, you can never compensate up front for the innate human ability to change something to suit its needs. Therefore adapt or die. I am certain triple even quad flares were never intended but hey someone figured out how to squeeze out every last ounce of dps a Black Mage could muster from the skill. Does that mean they are a bad player? No. They are inventive. Most likely they found themselves in a situation that called for it and thought hey I can do it this way and get better results! Necessity is the mother of invention.