You're absolutely right about the amount off work that can be done in Post. Even with just some basic adjustments in Photoshop like curves, the render already improved a lot.
I've already been fiddeling with this scene to long on the Maya side of things. Everytime there is a little improvement but not the major improvements that can be achieved through post.

Hope I got some time this week to delve into render passes and the Mila material.