Why don't Paladins have any unique "Cures"

[Viridiana]

Mind is about 5% of the reason cures don't work for paladins. The majority of the healing potency comes from the magical damage on the weapon. Swords have 0 magical damage therefore they get the base potency.

Not zero. It just doesn't display in the game. If you look it up on xivdb, you can see the actual scores.