They're not comedy focused, but I can only describe it as "Blizzard humor"... seems like all their games have a funny charm to them that generally focuses on light-hearted dark humor (is that a thing?), from the characters to the visuals to the quests and dialogue. It's present in all of their games.
Heck, I even like their slapstick, such as this brief little cgi video about the reaction to Mists of Pandaria:
https://www.youtube.com/watch?v=jon4GV1u3uM







