The WoD drops whatever is least needed based on the party. That is my theory anyhow. I always get NIN drops when we're full of casters, bards, or dragoons. I always get Dragoon drops when there's a ninja in there but no dragoon. And bard ONLY drops if we're all casters. Tank drops are the rarest from the runs I've done, and until recently, my first run was the only one I saw any DPS caster drops. So again, my guess is that it's secretly the RNG spiting whoever is in the party by dropping what they least need. It knows you're going to keep running it. It KNOWS......