Attender Can Get Beta Invite by Playing Warlords of Draenor at PAX East 2014
Here is Warlords of Draenor Beta invitation card at Pax East. I think tons of WoW players want it, even are willing to pay for it.
Here is the station for playing Warlords of Draenor demo at Pax East.
As of now, this is the only way to be eligible for a future beta testing. Checking the twitter, you will find that plenty of people are complaining that Blizzard have not yet to give out beta keys at BlizzCon last year as well. The next large game exhibition that Blizzard will attend with Warlords of Draenor next should be E3, which won't be available until June. So if Blizzard still won't open up other ways to release Beta keys during the following two months, we might consider to head over to E3 to take a chance. Anyway, stay tuned.