Shroud of Saints mana regen should not be static

[Syncness]

Casting Cure I 30 times takes 1 minutes (no spell speed) which costs you 3990 mana. Assuming a mana pool of 4000 that would be 99.75% of your mana but during that same time you will have regenerated 4800mp ((4000 x 6%) * (60secs / 3))

Assuming a mana pool of 5000 that would be 79.8% of your mana but during that same time you will have regenerated 6000mp ((5000 x 6%) * (60secs / 3))

When using cure 1 you will be getting back more mana than you burn through. Using your other heals is what pushes you down. The larger your mana pool the more tolerance you have built in to use those other heals.

Shroud is for when you need a large number of those other heals and need to stabilize after or get caught back up a bit because you didn't weave in enough Cure I to keep your mana stable.

Good insight, but missing the point. The discussion isn't what is the use for shroud, is that it's mechanic will make PIE worth less and less for WHMs.

The proof is in the pudding.

Yes and that is to show that one healer class has gains outside of innate effects of PIE whilst the other has none. This is not the discussion, this is pointing out that a stat isn't useless like the tank equivalent of STR since both tanks have minimal gains from it.