Wait what?
Do you seriously think that vanilla raids are so hard you cannot complete them all without being the optimal class/race combination?
Never heard that one before... its mostly the opposite. People who were legit farming naxx back in the day didnt gear "inefficiently" nor were they stupid either... but they knew that skill > race+class-combination.
Its really some next level elitism if you think simply playing your class well and optimally isnt enough if you dont have the correct race.
Everyone who knows atleast a little bit about classic know that races only provide minor bonuses such as humans having minuscule amount of more dps, in general, than other warriors because they had sword/mace racials and swords were the most common weapon drops in raids. But by no means were classic raids as enrage intensive as retail.
Lets get back to dwarf priests... your claiming its SO "important" to have fear ward aka all priests should be dwarves... but how useful will fear ward actually be? how many bosses in classic raid content even do fear? And how many of them cannot be avoided in other ways.
Correct me if im wrong but there are 63 bosses in classic, 5 of which have fear. So in 58 bosses fear ward is useless.
So in general having one dwarf priest in the raid is enough... since maintank is the only one who really needs it. If you have more... congratz it will help on those FIVE bosses.
I highly doubt blizzard designed the bosses for fear ward so they are very much doable without one... just needs a little bit more of that rare "skill". :P
Also if you spent any time looking at real vanilla world first guilds you would notice they didnt stack dwarf priests. As the screenshot i show proves... if that guild isnt convincing for you then go and watch some Death n Taxes-boss kills... they were legit world first naxxramas raiders back in the day, competing against Nihilum.