Passing the coursework does not require one to be a gymnast, in any school that teaches something that deserves to be called "martial arts". It should require that you be able to perform specific techniques properly and with power. There's no reasonable reason to expect that your kick be done at a full split, after doing a double back flip with a half twist. That's gymnastics, not martial arts.
To continue your college analogy, a tornado kick is the equivalent of calculating the cube root of 184.792 in your head. Cool if you can do it, but not really all that important.
How about a spinning hook kick, head height? Do you feel that any TKD black belt should be capable of that, or at least should've been at the time he/she received their grading?