I honestly do not think the way battle works in this game that a true support role would work. We have so few buffs and debuffs that its just not really necessary. How many times can you cast "attack up"? Without hastes, sleeps, refreshes, slows, gravity, resistances and so on a true support class would be very dull and needless since it would be more worthwhile to just bring another dps.

Support jobs are great, in XI bard was phenomenal and was highly sought after due to the way combat works. But really dnc is as close to a true support this game can really handle without a complete redesign of the combat system and since Yoshida was eager to remove stats, elemental wheels, debuffs and what not because he feels its just too complicated for today's gamers, its clear that will never happen. And frankly it would confuse the sticks outta ppl who never really played a game with true support class.