Set-up question

[robertrex]

I am working on a more precise set-up - right forearm on plane, etc. Here's a question I can't seem to answer for myself. What's wrong with a set-up that looks like Todd Graves/ natural golf? Specifically, what's wrong with having the left arm and shaft in line - or close to it?

When I set-up with a hitter's set-up I do alright. Every once in a while, I set-up more like Moe Norman. My position at the top improves. My pattern improves. Maybe even more importantly, the herky-jerky leaves my swing.

So my question is, what makes the set-up I'm learning a better set-up?