The Flash Heal/Inspiration build is a powerful alternative to Master Healer and Holy/Disc for end game.  This build requires require Tier 0 gear to be successful, specifically anything that provides a bonus to spell Critical Strikes (Rod of the Ogre Mage, Eye of Rend, Belt of the Archmage,  etc). The minimum crit suggested for this build is 10% with a goal of 20%. Luckily for a Tier 0 priest, this is not difficult, since a Tier 0 priest should have around 350 Int (3.5% base crit rate) and Holy Spec gives a +5%. This build looks similar to the Standard Holy/Disc build, with the exception for 5 points in Inspiration instead of Subtlety. This results in the priest generating more agro, but by this point the rest of the priests party should have progressed to the point where they can deal with this.

In essence the priest spasm Flash Heal and Prayer of Healing on his party. Every time their spell crits, the target gets a bonus 25% armor for 15 seconds, thus lowering the damage they take by 5%, (though this varies depending on the Armor of the Target and the Attack Power of the Mob, both sliding rules) requiring less healing.  This build is as versatile if not more than the Holy/Disc build, and is the optimum build for keeping an AOE’ing Mage/Warlock alive

Typically this build casts renew less (thus not gaining the improved renew talent) because renew cannot crit, though in boss tough fights, the priest will keep renew on his tank.  Some variants of this build bypass Agility and Inner Focus, or pick up Martyrdom/Focused Casting. Some even pick up Wand Spec (since the priest has more free time than a Master Healer). Most pick up Meditation for the longer mana bar. A priest may pick up spirit of redemption (post-humus critable).  This build is exceptional for Player versus Player, with its versatility.

The disadvantages of this build are that the priest generates more agro than other priest build and though the criting provides a better efficiency than the traditional Holy/Disc build, does not provide the efficiency of Master Healer. In addition, like all holy builds, the priest cannot solo.