The next expansion has been previewed

I didn't see it myself, but someone put together this album which has some of the information that they showed: http://imgur.com/a/kiFqg

Some quick highlights:

• New class - Demon Hunter!
• Separate system for PvP talents / abilities
• Artifact weapon you level up
• Instead of single person garrisons, you'll be chilling in a specialized domain for your entire class