I thought they said dragons can attack anytime and anywhere?
Unless they can't see you through the dense vegetation. It IS a forest. Do you know how hard it is to spot a single person in a dense forest?
Destructible Environments has already been confimed, just not confimed to the extent you are talking about, yet.
Would be way cool though!
Where is it confirmed?
Edit:
They can spawn pretty much anywhere. Was stated before.
Plus in the video the dragon "noticed" the player in the dense forest. Watch it again and you'll see it's obvious. The player was fleeing from the dragon. How bizarre would it be if he was somehow "safe" in the forest. Come on.
If the dragon gets a killing blow (by magic or arrow), then it will go down into the trees.
Destructable environments isn't some magic to do. So many games have it, one way or another. It adds a lot to epic situations. Seems a lot easier just to add destructive environments than changing the AI behaviour to somehow exclude from all the forested areas in Skyrim.
Dragon didn't spot anything in a dense forest. You have an overhead view of a forest (maybe to simulate dragon's viewpoint), and the viewpoint of running Dovahkiin. Then you see third person Dovahkiin at the edge of a cliff at the edge of a forest. Was he being chased? Maybe. But who is to say he was spotted within the forest? Maybe he was spotted outside, and he thought he could lose the dragon in the forest, but, by actively looking for him and knowing his prior location, the dragon was able to follow.
Now, it would svck if they made it so the forests were completely dragon-proof, but it would also svck if all the vegetation in the land got wrecked to [censored]. This is TES, not [censored] Fallout.