Being in full 3D actually hurts the games chances of utilizing moving parts because of the added complexity of AI creation. Usually, in the rare instances it is done, the AI is either scripted to use the terrain features under specific circumstances designed for a specific encounter (a lot of time investment so you want to make sure it's a really important encounter) or designed to be robust enough to intelligently use moving platforms to their advantage in pathing. (which is much harder and even more time consuming, and as an added topper usually creates abuse-able behavior) You then also need at least two people to work on the assets to make the feature work. A graphics designer to make the models and hopefully one that knows how to do their own rigging, as well as a programmer to add it properly and set up the pathing maps to incorporate it. After all that you have one encounter that is slightly cooler than average... It could be done, yes, but it's probably not worth the hassle.
Perhaps my understanding of how it could be done more cost effectively is flawed but the above is basically why you only see moveable objects related to combat in 2D games where AI scripting is MUCH easier or when enemies have a method of ignoring the terrain like flight or even no clip in some cases. (Oh 8bit 2D platformers :P)
