It's true that Aleroth was meant to be in the original. If you jump over the barrier when you enter Aleroth, you can explore the city and most of it is intact. Some placeables and textures however are missing. To jump over the barrier, you'll need to jump up upon the flame holder that is near the barrier under the tunnel (the tunnel leading to the lift). From the flame holder, you can jump over the barrier where the soldiers are fighting the undead.
It's interesting to note that talking to one of the soldiers makes you go through the dialogue with Commander Rhode again and several of the soldiers are called "Man" which is quite funny.
So I guess this supports what Macbeth was saying about the time running out.
