I am not a Maya artist. I am debating a flame artist about a current job.

Maya is taking 15-20 min/frame to render, and the exr files are then brought into flame, where he spends 3 days "lighting" and colour correcting 30 sec worth of animation. He says it's faster to correct in flame than to re-render.

My argument is that the time would be better spent getting the scene right in Maya, so that every frame is complete once it's rendered. If (when) the client comes back for more, the scene will be properly lit, and the Maya artists just has to create the action with the existing characters in the existing (properly lit) world.