I don't really understand how people think WMH is that bad of a tank healer?
Physick(300p) = Cure I(300p) equal
Adloquiem(300p(300s)) < Cure II (650p) This goes a bit deeper, but Aldo is essentially a 300 actual heal, each with pros and consso comparing these 2, since the p/s effect on Adlo is situational, has strengths and weakness, it is best to say WHM/SCH is best together.
- Adloquiem 300p + 300s (600p/s total)
Crit heals provide double shield, so a crit will be 300p + 600s = 900 total value
Shielding in general has the effect of increasing eHP if used on a full target- Cure II 650p
Can proc free casts with Cure I
High actual single target healing (Adlo is half shield so isn't good to cast consecutively, provides less HP restoration)
SCH Eos/Selene is nice additional heal, 300p / 3 seconds cast, except pet AI is silly, also macros will slow your personal heals due to queueing issues
WHM Regen is strong single target heal 150p, but is "Set it and forget it" type heal over 21 seconds
SCH Lustrate is also nice, 25% hp restoration that makes up for their Aldoquiem only healing 300p on low HP targets.
I would say SCH may be a little better in tank healing, but WMH are quite good at tank healing with Cure II and regen.
However, make the comparison in AOE healing, and WMH blows away SCH completely, SCH cannot aoe heal effectively (yes, even with rouse/whispering dawn on a 1 min cooldown). Yes, you can 2 heal SCH/SCH Titan Extreme mode, but u can also solo WHM that fight as well.
EDIT: I want to get into the p/t healing combo a little more here. potency/shield combo, is what SCH relies on mostly, like Adloquim/Sucor
p/s (potency/shield) healing abilities compared to p(potency) only
Target is at full health: This will be more effective than a p, since it can increase the target eHP. A p heal would be 100% wasted here, but a p/s heal is 50% effective for shield (assuming the shield gets used at some point). If target is full health, and doesn't take more damage before shield wears off, p/t is equal to p in healing 100% wasted
Target is not full health: In the case that a target is not full health already, then at best the p/s combo can be equal to the pure p ability. Assuming the target will take damage in the future that will consume the shield 100%, then it will be equal to a p heal. However, in situations where the shield will not be consumed (fall off), or if another shield will be overwritten before it can be used (in the case of 2 SCH or consecutive casts), then the p/s combo is significantly weaker than the p only combo.
So in summary, having pure healing is almost always more effective or equal to having shield/heal, except in the case where a target is at full hp, at which point a shield can increase the eHP of the target. So SCH is just there to avoid 1 shot mechanics from going full hp to death quickly which is what the shield does.
Overall I think the WMH is still superior and has a distinct lead over SCH, SCH does add certain things such as shield, and damage reductions , however the SCH mechanics max at 1 per group as their benefit does not overwrite with multiple.