I was debating if I should even reply...I know there is a big rage for healers going on and anyone that posts something positive just gets shit on, but I'm going to take the chance.
It appears like SE wants to reduce the AoE output of healers, obviously. So removing Bane/Miasma 2 seems pretty logical and replacing it with Art of War, 150 potency AoE. WHM's Holy is 140 potency now and has a cast time. Having both Bane and Miasma 2 ontop of AoE would have been way too much AoE dps compared to WHM/AST. Since SCH are so keen on keeping Miasma 2, they can just reduce the potency of AoW and give it a DoT effect to make up for the missing potency.
And yes, I feel people are going to point out that WHM get Misery, but that would be once every 90 seconds so it isn't spammable vs a SCH being able to spam Miasma 2/AoW/Bane