I think Nolan wanted to say that having depth of field is redundant, because in real life it is your eyes that makes the focus on things. So having blurry parts on screen in a 3D movie looks nothing like "real life 3D".

I liked the 3D in Avatar, but having depth of field (making part of the picture blurry, to focus your eyes on something) was weird. I think in 3D movies the focus needs to be "infinite". Meaning no blur anywhere. That way the audience focus on what they want. Of course this kind of thing would lead to have the movies in two versions: one with depth of field, for a 2D exploitation, and one without, for the 3D exploitation. And I don't know if this is doable.