If Tobey Maguire was deemed "too famous" for Life of Pi, why bother casting him in the first place?
His days hanging on a wire-harness in front of a blue-screen for hours on end, and Sam Raimi torturing him, are over. He's amassed a fortune from the web-slinger to return to his character-actor days. What was intended to be one of those roles, a supporting turn as author Yann Martel in Ang Lee's 3D awards-contender, got the editorial axe. The part remains intact, reshot with Rafe Spall (one of the early victims in Prometheus).
Fear not for Tobey. The Great Gatsby is on the horizons, whenever Warner Brothers releases it, at least.