Seriously. I love the show more than just about any other current program, but that’s weak. You decide early on who Drew is, and you BASE EVERYTHING AROUND THAT! Any misdirections, any subtle hints, any seemingly meaningless dialogue, should, upon Drew’s revelation, make you slap your forehead and say, Of COURSE!"
What they did is LOST-level writing. Never do that.
If I remember right, they briefly considered Josiah, but they wanted to keep Josiah’s foot cut off, so that wouldn’t have worked. They also considered having Drew be one of those rich guys on the hill, but decided it would be more fun if Drew was someone we’ve met, not somebody totally new to the story. They then shot the scene where Shelby has Drew’s autopsy report on his computer monitor, to give us an early clue.