Blizzard has just announced a live developer Q&A taking place Friday, September 5, at 10:00 a.m. PDT on Twitch.tv. Community Manager Lore will be moderated the Q&A with Lead Narrative Designer Dave Kosak and Lead Game Designer Cory Stockton as panelists. The focus of the Q&A is, of course, Warlords of Draenor. You can expect information about garrisons, questing, new features, and general world design. Given the absence of Celestalon, it's doubtful questions about class design will see much traction.
Though the Q&A isn't until Friday, you can begin submitting your questions on Twitter with the hashtag #WarlordsQA.