In late March 2006, Blizzard had an April Fools joke about a new playable race: Wisp. Obviously this was a joke but a month later the second playable race in The Burning Crusade was announced which was the Draenei.
This past April Fools joke, Blizzard mentioned a new Hero Class: The Barb. The joke was hilarious but is Blizzard going to follow the same path, which they may introduce a second Hero Class.
I truly hope so.