For the most part, Final Fantasy VI's large (by RPG standards) cast of characters helps the game. As a first time FFVI player, I can tell the depth of the majority of the characters as a crucial aspect of the games plot and an element that compelled me to progress further and further into the game. Even the few exceptions (Mog, Umaro, and Gogo) do not hinder the depth of the overall plot as the other established characters have their personalities and actions indented into the plot firmly.
I am currently 30 hours in and this is shaping up to be the first Final Fantasy game that I will beat (XIII was the first that I played). All that is left is The Ancient Castle, Ebot's Rock, Doom Gaze, 4 Dragons, The Fanatic's Tower, and Kefka's Tower.