I don't need to say this again, but...
That gear guide is poor.
Mind > Determination > Piety > Spell Speed > Crit
Heal potency, heal consistency, longevity, reaction time, over-cure.
Larger heals from MIND, more consistent high heals from DET, better regen & independence from PIE, better OH SHI- from SS, better enmity gain from CRIT.
As stated; fights are predictable. SS isn't bad, but isn't required if you know the fight. Consider 'knowing the fight' a stat that YOU, the player can level. Not your character.
Don't underestimate PIE on WHM. One significant pain-point of WHM is mana consumption. Any additional PIE is welcome.