As announced at Blizzcon, the character classes in World of Warcraft are going over a revamping to make them more in tune with the lore of the class and to make the different specs more distinct. There is also a move to streamline the game play. Yesterday we talked about Hunters as one of the most changed. The Priest class has also have some changes in the works especially to the dark side of the character… the Shadow Priest.
Again with the idea of the specs being unique not only in game play but in story, the Holy Priests are still mainly focused on healing. The Chakra system is being done away with as it was deemed too cumbersome and requiring far too much set up. It is being replaced with a new system called Holy Words with new spells that will cast large heals but with equally large cooldowns. They designers wanted these heals to feel 'miraculous'. Casting your smaller healing spells will reduce the cooldown of the larger ones. Also, Holy Priest can no longer use any of the shadow spells. Instead they will be able to inflict damage when necessary with Smite, Holy Fire and Holy Word: Chastise.
Moving on to the other healing spec, Discipline. This was kind of the joke spec for a lot of years as no one played it. You were either Holy or Shadow. But during Warlords of Draenor, the Discipline Priest returned to fashion with the ability to heal through attacking. But the problem was they did so much absorption with the shields they created that other healers were being excluded. So the designers are de-emphasizing the shields and replacing it with a reimagined Atonement mechanic. Their key will be balance between Holy and Shadow, dealing damage and healing. The will have a balance of offensive and defensive spells.
And that moves us to the dark corner of the class, the Shadow Priest. If it wasn't for the purple hue you'd think they were a Warlock. To change that, Blizzard is tapping into the lore that ties these fighters to the Old Gods and creating a new power mechanic for them… Insanity. Spells like Vampiric Touch, Mind Blast and Shadow Word: Pain will build Insanity and when maxed, shadowform will become voidform increasing the characters power for a limited amount of time. Voidform increases damage by 30% and haste by 2% every second but it immediately drains your insanity at an increasing speed so you'll want to save your cooldowns for that moment.
Looking at this overall, it feels like they are making the Holy Priest the top healer for the class with Shadow Priest getting a new mechanic and the Discipline Priest being nerfed back to pre-Warlords days. I would consider this a leveling class, you can do some damage but keep yourself alive… but in a raid I think you'd want to either be the best healer or best dps that you can be. Not a bit of both.
For more specifics on the class, check out the piece by Blizzard.