I wasn't paying attention when Richardson dunked, so I wasn't sure if he went through his legs. From the corner of my eye, it kinda looked like he just brought the ball down to his hip and then dunked it. But I was like "Damn, if Richardson went between his legs, I just missed the best dunk in NBA history!"
No question, it was the best dunk ever. Some dunks had more drama (such as Jordan from the free-throw line in order to beat Dominique), but based on degree-of-difficulty, Richardson's dunk is the best. For years, people have been saying that every dunk has already been done, but Richardson proved them wrong.