The new healer water cooler came out today with some great information.
Priests are losing many instant cast heals they currently have. Cascade, Divine Star & Halo now all have 1.5 second cast times. Prayer of Mending is now 1.5 second cast time.
Heal is being removed (although the name could be reused later).
Divine Star will be nerfed (sorry Priests!)
Divine Star is probably the most overpowered spell in the game, currently. It will be nerfed in 6.0.
They have also broken down what they see as higher efficiency heals vs higher throughput (but more mana expensive) heals:
Priest Higher Efficiency: Greater Heal, Circle of Healing, Prayer of Mending, Holy Nova (new Discipline-only version), Penance
Priest Higher Throughput: Flash Heal, Prayer of Healing
They plan to dampen down the amount of absorbs in the game, but say they will still be conscious of the fact that Disc relies on absorbs for its healing spec.
Additionally, we’re toning down the power of absorbs in general. When they get too strong, absorption effects are often used in place of direct healing instead of as a way to supplement it. We will, of course, take these changes into account when tuning specializations that rely heavily on absorbs, such as Discipline Priests.
There are some Atonement changes as well, according to Celestalon.
Atonement will not be as much healing throughput as normal healing. Does significant damage when you don’t need as much healing.