Every athlete has to be evaluated on many levels. Not only talent wise (where Wheating is a 99) but also the ability to stay injury free (think Rupp), willingness to do all the little things to improve (think Willis) and the mental part of sport (think Centro).
Although Wheating may rank above the others in talent, he's far far below them all in the other three categories. At the college level, where he was micromanaged by a great manager/coach and was competing against far inferior athletes, he got by. On the world level where he's largely on his own, his poor ratings in the other areas were his downfall.
For another example of an athlete like Wheating, see: Brian Bozworth