As you're no doubt aware Lou Albano was the voice of Mario in The Super Mario Bros Super Show but was replaced by Walker Boone in both The Adventures Of Super Mario Bros 3 and Super Mario World. However. According to a post years ago on the tv tome message board for the show Lou Albano was set to return as Mario and even recorded the first episode but was replaced after that. They even dubbed over Albano with Boone. No reason was given on why he was replaced. They did say the episode with Albano was Mario did exist and may be released as an extra on the then upcoming DVD's but obviously never happened.