I wonder if the change was to encourage level 60 characters to move from their old hunting grounds to the new ones.
I can understand why warlocks would not be happy. I’ll certainly understand it even more when I start leveling my warlock again. *grins* Obtaining new shards is a major pain in the backside. Hunters also rely on consumable items for their damage, but a quick jaunt to a friendly vendor and they are ready to go again for many hours. Warlocks have to find mobs that give them experience and then kill them one by one to restock. And they can often find themselves in situations where they cannot replenish their shards. It’s obviously not a class breaking mechanic, but it makes the warlock’s ability to do damage, specifically having any pet other than a fragile imp, more difficult than any other class. And to now make gathering those shards even more difficult is not good news.
This will also make leveling up some of the new BC pets more challenging for hunters. But not so much so as to make it impractical.