tank in FFXIV : deal less dmg and make of glass
DPS in FFXIV : deal more dmg and make of super thin glass <--------- this one sound more fun

@on topic: the reward are fine for tanker, if ppl don't want to play tank, they don't want to play tank, simple as that. Add more reward "might" solve issue for queue (it is not like it is an issue anyway) for DFR but after that, they will go back to what they like, the problem remain