For the construction of the original World Trade Center buildings (WTC 1 & WTC 2 = 1400 ft +/-), there was concern about the swayying of the building, and what kind of design criteria they should have.
Thus, psychological studies were conducted at the University of Washington to determine the effects of motion on people's state of mind. The test consisted of people coming to a "doctor's office" for what they thought was a free medical check-up. However, the "MD" was actually a PsyD, Psychologist, and the "office" was on a shake-table.. or sway-table as it were. The sways began shortly into the "check-up", and got progressively larger.
The Psychologist documented, among other things, the time (a) when the subject showed a physical reaction (as small as a shift of the eyes), (b) when the subject showed signs of real disturbance, (c) when the subject voiced their concerns to the PsyD, and (d) when the subject ran out of the room.
Awesome.
The Twirling Tower folks probably did a similar study for tall building, plus a study of other building with rotatin resturants and what not. The building sounds like a pretty good idea to me. And if a few floors somehow stop moving, at least it's not like a draw bridge that got stuck in an upright position.