I think the scale per Lily would work better.
P.S.: IT DOES HAVE COOLDOWN REDUCTION.
Again I say it's just redundant. It's a faster SS with lower CD
In comparison to other jobs...I guess we can look at the fact you have
SCH: The main shield user.
AST: Noct AST.
WHM: Instant SS, low CD with cooldown reduction.
No reason for the other jobs to have their own shield plus SS, but this did help SCH have double/triple shields.

I wouldn't mind seeing a tiny buff such as Scale per Lily idea.
WHM does need a little bit more love. I would be happier with the original 18% "Granite Skin"
and keep the CDR of the Lilies but I guess they can bump up the recaste time if they want.