Well I haven't played every MMO ever made, so I can't really speak to things that are totally original in the game, but there are several things that are at least rare in the genre:
1. The Progression System: Pretty free form and open ended, lots of skills and lots of ways to obtain skill points, no hard class system
2. The Combat: Not quite full action combat (because no free-form aiming) but far and away from tab-target MMOs
3. Limited Skill Bar and No Cooldowns: Ties in really well with the first two, but there are far fewer skills available at one time, which makes the choice of each skill slotted more important and strategic. There's also no cooldowns/rotations, everything is resource based.
4. Limited UI: Like an Elder Scrolls game, there's not a bunch of junk on your screen
5. The AI: It sounds like the AI will be innovative (but all devs say this) for the genre. Creatures will work together interactively and the threat mechanics will be more realistic.
6. The Lore: It may sound like a copout, but this is the only MMO with the TES background, history, and setting. That is and should be a selling point for many people.
There's probably more things I'm missing, but the Important thing is that while not any one feature can be completely unique, the particular way they are implemented and the combination of them into one game can still be unique.
Games are holistic experiences. The sum is greater than the parts. Its how all those things work together that really matters.
EDIT:
Like others said:
7. The mount system
8. The megaserver
9. Persistent PvP (meaning the world doesn't reset ever), which again isn't new but is rare