Animated 3D models that are not animated on pre-set, pre-designed animations but see the game generate the dynamics of the animated movement through a combination of environmental and action based 'rules'; the accumulation of animations on the same object/avitar.
Examples:
avatar jumps, pre jump rules applied (key-pressed) post jump rules applied (key-release) (separation)
rules unable to animate walk movement when hitting objects such as walls (environmental rules)
climb animation rules can use hight of object to change animation metrics (environmental variables)
cat avatar waggles tail, walk action added, tail movement not interrupted (accumulation)
walk or run speed reduced by spell, animation reflects change. (status variables)
As you can see you need to be able to move the animated 3D objects from the stored file into the generated realm and that might be quite hard to do. you would need to not only specify a model but instead of pre-set animations you would have a set of dynamics which encode for the models change in position.
Although it does strike me as unique in RPG terms.

It would cerainly add complexity but would create a better sense of reality lacking in most walk about games.