the 2pc is pretty badass, especially for healers. since 4pc healy bonus sounds like another "click the god damn light well" mechanic, I'm sure a lot of healers will go 2x Heal and 2x Shadow
The 2pc is decent. This really depends on what you are assigned to and if you are disc or holy. Raid healing, for example, has disc priests spamming shields, PoH, PoM and penance mostly and holy does PoH, PoM, CoH and Sanc. I guess during intervals with no raid dmg we could Heal to gain mana, though. I'm disappointed with the 4pc. Its hard enough getting ppl to click my lightwell. Why couldn't it be like the pally 4pc (Holy 4 Pieces - Your Divine Light also heals a nearby injured target for 20% of the amount healed.)? Free extra heal on your most used/spammed spell is pretty OPed.