Lucas is under the mistaken impression that the Prequels are far, far, far, far superior to the Original Trilogy, so he takes any opportunity to bastardze the originals with more and more Prequel BS. This is one change that I am amazed to see the Lucas-loving Fanboys standing up for, as I can see no logical reason for the change.. other than ego and a need to make ROTJ (a movie Lucas did not write or direct) even more a "Lucas Prequel".

Or to put it a better way, Hayden was not even born when SW was released.