Darth Maul
I've always wondering why George Lucas decided to kill off his most compelling character in Darth Maul. Couldn't he have let him live to be the main antagonist for Obi wan Kenobi and Anakin? It seems like such a waste to kill off the best character in all three prequels, in the very first film.
Maybe if he would have been around for the 2nd and 3rd films the movies would have been received differently.