Once you know the Instance, tanking really isn't that hard and the instant queues for DF are really nice. The problem is that, compared to DPS, very few people want to go through the trouble to level a tank, get the gear necessary to be successful and learn the instance from a Tank point of view.

EVERY game out there has this same issue. Tanks get instant dungeon groups, Healers nearly so and DPS have long waits. The difference with FF14 is that YOU have the power of your own destiny in your hands. You can level a Tank class (or a healer) and still accumulate points and gear for your preferred DPS class since it's one character / all classes.