Mark,
I'm weighing in on this subject a bit late but my opinion is the prospects look grim. As a painter from way back, TD's have been trying to push those filter scripts on me for years to try and get that painterly look. The major problem with it is it treats everything the same and so important details get more processing than they should. 

Separating the layers, as mentioned above, can help. Smudging everything with a brush is tedious and in the end will require some painterly skills as everything shouldn't be smudgy.

Martiniere, while I don't know his process, I do know there are people who can paint that kind of technical detail from scratch. I must admit while I started off there I find it easier to let the 3D program figure out all those shadows and reflections for me. 

While he may go very painterly with background and foreground details his focus remains sharp on panels and gizmos, appropriately. 

For me, I've been trying to find some way to drag my 3D illustrations back into the paint world but I've never been satisfied with any of it. It always ends up where I'm having to work over every inch by hand which might return some warmth to the image but puts a serious dent in my schedule. 

Whichever way you finally decide to go, I hope you choose to keep some of the details sharp.