What makes WHM special? Nothing anymore.

[Coltvoyance]

would like to know how instant casting a heal every GCD makes it 'faster heals' compared to a skill that makes the actual gcd shorter

You're right, looking at the numbers more closely, PoM will allow a heal every 2 seconds, while AST's Lightspeed will give a heal every 2.3 - 2.5. However, even with PoM a Medica 2 will still take roughly 2.3-2.5 seconds. Where as an AST's AoE Heal will take 0.5 seconds to cast, making the FIRST heal happen sooner, in addition to the 25% MP Reduction. I'd be willing to concede that these are comparable rather than a win for AST since WHM will get more of them off, but AST has that MP reduction. I'll change the tally for it.

[Muahbec]

You're right, looking at the numbers more closely, PoM will allow a heal every 2 seconds, while AST's Lightspeed will give a heal every 2.3 - 2.5. However, even with PoM a Medica 2 will still take roughly 2.3-2.5 seconds. Where as an AST's AoE Heal will take 0.5 seconds to cast, making the first heal happen sooner, in addition to the 25% MP Reduction. I'd be willing to concede that these are comparable rather than a win for AST. I'll change the tally for it.

You want an instant Medica?
Swiftcast!
I can say, when i play as AST i never use Lightspeed for the "instant heals" since it won't increase my output, and yes for the "reduced mp cost".

[Rewind]

You're right, looking at the numbers more closely, PoM will allow a heal every 2 seconds, while AST's Lightspeed will give a heal every 2.3 - 2.5. However, even with PoM a Medica 2 will still take roughly 2.3-2.5 seconds. Where as an AST's AoE Heal will take 0.5 seconds to cast, making the FIRST heal happen sooner, in addition to the 25% MP Reduction. I'd be willing to concede that these are comparable rather than a win for AST since WHM will get more of them off, but AST has that MP reduction. I'll change the tally for it.

PoM is not SPELL SPEED anymore!!! It's attack speed only.

[Crater]

PoM is not SPELL SPEED anymore!!! It's attack speed only.

"Attack speed" is a generalized term for any haste buff. It affects healing spells just as much as it affects offensive spells.

The minutiae of how "attack speed" differs from "skill speed" and "spell speed" are a tiny bit complicated and largely irrelevant to WHM, but the short of it is that Presence of Mind is effectively a 25% boost to (non-HoT, on-GCD) healing throughput.