The trouble with being Blizzard is any new game it makes is bound to steal some thunder from World of Warcraft, the very game that made Blizzard an online powerhouse to begin with. And while Blizzard’s upcoming Titan MMO looks to be the biggest threat in this regard, studio co-founder Frank Pearce believes Azeroth is in danger of losing some of its adventurers even sooner to Diablo III. …