@moviemaker:
I watched The Kingdom.
It is beautifully lit and scored, but it is not a great example of physical animation. I noticed that much of the animation was copied and pasted from one character to another (ie: groups of avatars behaving with the same motion).
It is impossible to tell if any of your characters maintain a consistent or unique personality.
The characters also lack what is called "intentionality" which is the INTENTION of DOING or THINKING or NOTICING others.
Without "intentionality", your characters do not seem to notice each other or perform actions which are not simply pulled from the animation library. Dead and robotic, in other words. That's suitable for AI characters in video games, but not so suitable in the service of a narrative film. If your characters do not "believe" in what they are doing, the audience won't believe it either. When characters only perform canned motions, you don't believe they are going to do anything unique or meaningful.
In my Reception Office video, those characters each have an agenda and a sense of "awareness" about what is going on around them. They INTEND to do something and their personalities are fairly distinct.
None of these issues need to be solved by mocap--- but I did not notice much in the way of keyframe animation in your example. Keyframe or mocap, take your pick, but it is laziness not to use either one.
You should have called your example "a well made iC movie without mocap -- or motion layer editing, or facial animation, subtle movements, or custom motion of any kind" !!