At launch, priests had some strange issues, such as Inner Fire providing attack power — a holdover from when the Discipline tree was planned to be a melee spec like today’s Windwalker monk. But vanilla priests faced no bigger aggravation than their class-specific racial abilities.
In vanilla, five races could be priests: night elves, humans, dwarves, undead, and trolls. Each provided a priest with two race-specific spells. If the abilities had been similar, with slight variations, they might have been a welcome and flavorful addition to the class. This was not the case. The racial abilities were wildly different in both utility and power.
Humans were generally considered to be the worst race for a vanilla-era priest. They had a self-heal on a 10-minute cooldown (the original Desperate Prayer) and Feedback, which granted a short-term buff that burned mana from any caster who hit the priest with a spell.
Dwarf priests were on the other end of the spectrum. They were the only priests with Fear Ward. Fear Ward was incredible in both PvP and PvE. Vanilla bosses loved to fear tanks, which could be devastating if not handled properly. A few dwarf priests in the raid could completely nullify that mechanic. A dwarf priest was an auto-invite for most raiding guilds, regardless of the player’s gear, skill, or attitude. Fear Ward was so powerful that it became the first priest racial to become trainable by all priests, in patch 2.3.
For priests, the choice of race became paramount, and it was a choice that new players didn’t know mattered when they created a character. To compound the problem, Blizzard hadn’t yet offered a race change service, so race was a permanent decision. Plenty of priests reached max level, started raiding, and then felt compelled to create new characters of the “correct” race when they figured out that the racial abilities had such a big impact on their contribution to the team. The racials also became a point of contention for Horde players, who had no access to Fear Ward at all.
Blizzard carried this idea into The Burning Crusade. Blood elf and draenei priests both received two racial spells (although one of the blood elf skills was shared by undead). Ultimately the idea was abandoned in Wrath of the Lich King and most priest racials disapppeared from the game. Devouring Plague, Hymn of Hope, and Desperate Prayer survived and became available to all priests. Chastise later made a return as Holy Word: Chastise in Cataclysm.