Even if they did put an official voice chat in the game wouldn't it end up being ignored?

Blizzard put in official voice chat for WoW and guess what nobody uses it because Vent/Mumble/TS/Skype offer better quality, and people prefer their 3rd party VoIP programs to one that's provided in game. People in a guild rather pay for their own vent or mumble server then use the in game voice chat.