Confirmed at BlizzCon 2013, the fifth expansion for World of Warcraft is called Warlords of Draenor as a recent trademark listing indicated.
If you're hoping to jump right back into the action, here's the good news: you'll be able to instantly boost a single character to level 90; that goes for new and returning players. The level cap has been bumped up to 100, and the expansion also brings "revamped" character models and animations for some of the playable races. That's the good stuff right there.
The other feature I'm liking the sound of is the ability to construct strongholds, called Garrisons. You'll get to set one up, recruiting NPC allies for your cause. Warlords of Draenor also promises changes to questing that will "encourage exploration and add unpredictability" as well as the expected inclusion of new Zones, Dungeons, Raids, etc.
The game's subscriber base may be on the decline, but this does sound lovely. I can't get enough of Grom Hellscream.
World of Warcraft: Warlords of Draenor Revealed! [World of Warcraft]