How was the arthas/illidan fight done?

I haven't opened the map yet to look at it, but is the fight a giant model with animation or is it hardcoded or what?

It is one, or maybe two, really high-detailed models. The rest is essentially camera angels and zooming.

In fact, all the preview screens for the campaigns are also high-detail models. They're accessible from the model list in the standard TFTWE (under "extras", I think).

what about the running sword slash overlay (which was animated)? not to mention the cinematic models don't appear to have any animations

the terrain was a bit too good for regular terrain too, unless thats was a specially designed model too