(Stolen from the thread on the Blizzard Forums)
As has been stated many times in recent posts, a number of improvements are being made to several priest talents and core abilities for the next content patch. Several of these changes are still in the testing process, and in some cases, under discussion - especially those relating to talents. What this means to the players is, the following details pertaining to upcoming change is not comprehensive, and intended primarily to serve as a sneak preview, and in a perfect world, satisfy some of your curiosity.
Too bad this world isn't perfect...
Greater Heal (and Heal starting from rank2) will receive a reduction to its casting time. Currently the spell is a 4 second cast. However, once patch 1.10 releases, the spell, from start to finish will cast in 3 seconds - (2.5 with talent improvement). This spell, along with the Druid's Healing Touch and the Shaman's Healing Wave will all receive an approximate 10% improvement to mana efficiency.
Holy Fire will no longer be a talent required ability. All priests, upon reaching the appropriate level will receive this spell as a core ability. In addition, this spell's casting time has been reduced from 4 seconds to 3.5. The appropriate talent improvement would bring this spell to a 3 second cast. This spell will also be considered holy damage, meaning, effects which improve holy damage will increase the damage of this spell.
Inner Fire is another core ability we're reworking. With the prevalence of wand-use amongst casters, we're not very pleased with the increase of attack power this spell provides and are looking to change Inner Fire so that it is more in line with the original concept behind the ability, i.e. a defensive/soloing spell.
Power Word: Shield is still undergoing testing. Basically, we're running the numbers of the final spell ranks and will likely make changes to its damage mitigation scaling.
Talents are where we're making the most significant changes, however, until the changes have been finalized there is little I'm going to be able to reveal. What I will state is that we're reorganizing and streamlining all three trees, with a particular emphasis on Holy and Discipline. Each tree will have anywhere from 1 to 4 brand new talents available. The focus of Holy will be in providing throughput improvement, such as offering benefits to healing and spell damage. Discipline will focus on staying-power, such as what you see from abilities that improve mana and mana regeneration. Shadow of course, will focus primarily on damage.
Priest class racial improvements are for the most part, complete yet undergoing testing. Until all of them are ready to be unveiled, I'm going to avoid providing specifics. I will try very hard to push out concrete details late next week, if possible.
A number of minor improvements and tweaks continue to be made as well, such as the increase we're making to Prayer of Fortitude's range and radius, the overall reduction to Smite's mana cost, the addition of group buff versions for Divine Spirit and Shadow Protection, and much more. In addition, I can promise that I'll push for the talents to go live on the talent calculator the moment that they've been finalized, which hopefully won't be long now.