SCH is the OP one.
Embrace -> passive regen + rouse buff
whispering down -> aoe healing
Fey union -> basically like spamming mini cure/benefic to target
This combination makes the burden for both healers lighter.
It is like Eos says "do not worry just keep dpsing or doing another stuff (like raising), I will handle the heal"
Is it possible for WHM/AST to do this?

I think SE starting to reduce SCH power by lowering both embrace and whispering dawn potency compared to HW.
But they are still OP until now.