Why these changes weren't relayed to investors or the press is still unknown, but it's likely due to the fact that they could be interpreted as a sign of weakness. Activision has seen flagging sales for two of its former cash-cow franchises, Tony Hawk and Guitar Hero, and a recent very public scuffle with Call of Duty creators Jason West and Vince Zampanella following their ejection from their positions as heads of Activision's Infinity Ward studio painted the studio in a negative light with gamers. This kind of restructuring could point to turmoil within the company, an image that an industry juggernaut like Activision would want to avoid.
So, what do these changes mean for Blizzard, and for World of Warcraft? Activision got a hold of us to say "nothing at all" -- the restructuring was for Activision's side of the business only. It's important to remember that Activision-Blizzard is an umbrella company that contains two separate divisions: Activision Publishing and Blizzard Entertainment. Activision restructured into three different units, but Blizzard remains independent.