Big Pro: Just look at what Robert Kirkman did with Invincible. He created a whole world around the character and Mark was able to affect and have an importance to his world that Superman just can't have in the DCU.
And Invincible World is a big and diverse one, full of sci-fi and concepts that Superman have been lacking for a long time. Invincible War, Conquest, Viltrumite War are examples of big story lines and events that, honestly, dwarfed almost everything that happened to Superman in the last decade, imo.
Superman have 2 comics every month, in a perfect world DC would make one it's own universe, an elseworld where only Superman mithology exists.