My main is a Draenei and I've always wanted to explore deeper into their past and culture. In fact I posted about it a while back. Obviously this expansion will really allow me to learn about Draenor, the Orcs and Draenei and the origins of the Horde and how Outlands came to be. Speaking of which, I'm quite the fan of Outlands as we know it - mostly due to the very unique spacey feel that it has. Obviously, Draenor will have a similar feeling which I'm looking forward to.
New characters models is something else I've wanted for a while. Back in July, a Community Blog Topic asked What is your favourite playable race? and I answered Gnome and Tauren's closely followed by Draenei and Goblins. And I'm sure in another post I spoke about my personal preference for the older races to be re-vamped rather than new races and/or classes. Well, it looks like Blizzard took note of this general want! If you go to the Warlod of Draenor website you can see what race models they're working on; Human, Dwarf, Night Elf, Gnome and Orc, Undead, Tauren, Troll. Some models are viewable now and more will be in the future.
Storage has also been looked at! We can expect to see new ways to store heirlooms and toys and possibly *fingers crossed* tabards so that they don't occupy valuable bag space. This was a feature that I really wanted to see implemented and posted about back in June. Plus we should be seeing new ways of customising our bag space and an inteface update that should make it easier to identifiy purple epics from vendor trash.
In the same post on features I spoke a little about galleries/museums - essentially player housing. WoD brings us Garrisons - a very unique new part of the game. We will be able to build our own garrisons, upgrade them, have followers, craft items, invite guests to see our garrisons etc. I'm very excited about this and for more details I'd highly recommend reading some official material on the matter.
All-in-all I can't wait to step foot on Draenor!