Blizzard should have expected a Discipline Priest to Shield spam when they tie 80% of our talents and mastery to a single spell, while Holy Priests have their talents spread evenly amongst all of the Holy spells. Discipline Priests' full spell book is one spell and that's Power Word: Shield, because our talents do not buff any of the other healing spells directly. And do not give me the Discipline Priest has Holy Spells excuse, because Shadow Priests also have Holy Spells but they don't heal in raids.
And this change is just pathetic. Discipline Priests already have the weakest mana regeneration in PvP, and this change just further nerfs Discipline mana in PvP while offering nothing to Discipline Priests that would have them save mana in another area. And as the poster above me have stated, now Holy Priests can bubble spam with Body and Soul and Soul Warding, so basically Discipline Priests lost their signature spell while Holy Priests got the ability to bubble spam on top of everything else that they can already do better than Discipline.