Bring back 18% Stoneskin

[Lorglath]

Maybe factor in the third healer into your OP and you may get a better picture.

SCH and Noct AST are there to do the mitigation where it is needed.

WHM and Diurnal AST are there to do the bulk of the healing.

Give WHM both higher throughput of heals (which they have already over AST) and better mitigation than Diurnal AST, then you have less reason to take a Diurnal AST over WHM.

Then take away scholar's AOE healing.