Mike, can you proof that statement that the E3 stuff was scripted?
As far as I know the AI was given hints, by some sort of info_nodes. So, according to my information it wasn't scripted. It was especially said this strider ducking under the bridge was NOT scripted but AI. So I don't know what your source of information is?
Besides, why would Valve state they're working on revolutionary AI, that they'll be doing away with scripted action, and show us scripted stuff? I think some stuff will be scripted but probably only the necessary parts, like when a player needs to get some information from a NPC.
Heh, we'll find out the truth when the game is released...