When the developing staff says "unintended" it doesn't mean "lazy/stupid/inefficient". They could be implying that the player-base could be, well, playing in a manner that they [the developers] hadn't thought of. It happens in MMOs quite frequently. If a top-end raiding FC finds that it is more efficient in damage output, and time, to stack multiples of a single job, then they will do it. Less competitive FCs follow suit. And they will have the numbers to verify how it is efficient to do so. And when this happens, certain jobs get excluded due to inefficiency. "Yeah, we'd take more of X class if it was more efficient to do so."