You do to make it entertaining...Why would anyone want to see something that was done already?
think of it this way. there's a difference between say a nate robinson doing the same dunk and a dwight howard doing the same dunk.
the dunks might be the same, but the style and execution of the dunk is different.
you do a between the legs vince carter slam and your lebron james next year at the new dallas arena i guarantee you got the crowd jumping to there feet. same dunk, different execution and style to it is enough to get the crowd going wild