If they were to do anything, I'd argue that they should split crit rate and crit strength into two stats (so crit isn't the biggest godmode stat every time), make DH be the 'DPS only stat', make piety gain damage at the same rate DET does now, and then just remove DET because it's boring as hell as a stat. That way you'd have:

Tank: Crit Rate/Crit Strength/Tenacity/Skillspeed
Healer: Crit Rate/Crit Strength/Piety/Spellspeed
DPS: Crit Rate/Crit Strength/Direct Hit/Skillspeed (or spellspeed for casters)

Maybe merge the two speed materias into a single 'Speed' type too, which would benefit certain classes like PLD or DRK, who have some spells that are locked at 2.5 because spells do not get anything from skillspeed.

I really don't like the idea we have now, of 'the DPS stat DHit' being melded on every class, I think it'd maybe be better for the roles if they each had their own unique stat that benefits only them. DPS are set apart because they can Direct Hit for more damage. Tanks are set apart because they can get extra tankier via Tenacity. Healers are set apart because their healing power and MP regen are boosted by Piety. DET is the flattest blandest most boring stat designwise