well watch the trailer... if its true that only the wall is not in game, you can see the dragon doing some pretty random stuff, bashing you with his head, breathing at you, flying around and doing swooping attacks, the monsters seem to have randomized attack patterns for sure, but animations.... lots of work, i have an idea for this tho, animations on NPC's could be determined by skill level? for example an npc with a 100 hand to hand skill would go bruce lee on your butt while a npc with 10 hand to hand would attack like a total idiot swing around their arms like a zombie or that guy in two worlds 2? or a guy with 100 in the blade skill would kick your butt Kendo style while one with 10 would swing his sword around like it was a blunt weapon? then for monsters just based on the difficulty mode and what they are balancing it around between those 2 things they would change their animations and make them more confusing so you wouldn't know what he's gonna do precisely, like for example, a dragon. instead of just opening his mouth and breathing fire on you, he would pretend to be going to do that but then get you with a tail rake, then proceed with that breathing (tactics)
Basically what i think would be the best solution for this would be like 5 or 6 presets of animations for each npc and monster based on their skills and level and your difficulty setting. This would not eat up a lot of hard drive space (and besides who gives a damn about that hard drive space) but this would be a lot of detail work and something to think about for the bethesda animations squad
i think they could pull it off. i'd like to see something like this, make the characters and monsters unique and different from one another, just like 2 hands 2 options, 2 monsters 2 different AI's and possibly animations and tactics and difficulty (could even think of teaming up and not charging you head on but using tactics on you and try to kill you the smart way depending on how smart the creature is, a wolf would do that right? wolves are pack hunters, they never travel alone.)
Edit: the hard part about this idea of mine is that it would have to be a part of the game engine that the same creature doesn't have the 100% same AI or Animation set. otherwise there'll be a lot of.. hours of creation kit fun