The rule of "two misses equals end of round" sucks. If that was in effect, all you would've seen were safe dunks. Does anyone remember more than a few dunks from the entire decade of the 90's? I'm a nut for the dunk contest, but the only notable ones in ten years were Barry's free-throw hop, Ceballos' blindfold and Rider's through-the-legs.
If you want to allow for creativity, let them miss. Nate Robinson's figure-eight was sick. Iguodala being safe on that last dunk was not. All I know is, I'm going to remember Nate's two best, as well as Iguodala's pair, for quite some time..