Warlocks, as a class that was always meant to have mana and had a clear role in combat, fared better in vanilla than hunters. Warlocks dodged some bullets: beta’s 30-minute cooldown on Banish, for example, never made it to the live game.
Soul Shards were by far the worst aspect of vanilla warlocks. Shards were necessary for just about everything: summoning demon pets, creating Soulstones and Healthstones, and summoning players. Soulstones actually required two shards until patch 1.2 (although the 30-minute cooldown reduced the amount it could be cast). Each one had to be earned by killing a mob (or, after with patch 1.5, a player of adequate level) with the original Drain Soul spell.
Soul Shards weren’t just a time problem — they were constantly a bag space problem, too. They didn’t stack, even though you needed a ton of them for raiding. Early warlocks spent hours farming Soul Shards in order to prepare for raids throughout vanilla. Then, when they arrived at the raid, they were asked to summon . . . everybody else. Unlike today’s handy closets, warlocks back then could only summon one player at a time, at the cost of one shard per player. All that time farming, in other words, translated into saving everyone else time riding to the raid instance. Then you had to pray you could replenish your supply with trash mobs. During breaks, many warlocks were forced to leave the instance and farm shards rather than grabbing a snack. It was a giant hassle.
Blizzard somewhat alleviated the bag space problem by adding progressively larger Soul Bags to the game — up to 32 slots in Wrath. The fundamental mechanic, however, persisted until Cataclysm, when shards became a UI element — the mechanic for Affliction warlocks. Soul shards as farmable items are a thing of the past, and warlocks everywhere couldn’t be happier.