Shattrath Raid, followers having their daily routines and lines, capital cities, garrison being in any zone, destructible buildings in ashran, Tanaan being there at launch, Grommash as the final boss, more Ogre territory, Farahlon obviosuly, and heads of the elite you killed being mounted as trophies in your garrison.
On the top of my head.
We were also supposed to start at the "chronal spire" rather than where we started.
Edit: Oh yeah also the pet breeding system ;(
Damn. I didn't realize there was that much. Was it all actually announced as stuff that was going to be included for sure?