Motion blur is just a lost of focus on an object that's moves to fast at a certain distance from your eyes.  It's more like depth of field blur.
If something moves too quickly in front of you, you won't be able to focus on it and therefore, motion blur - though farther away it will either be too small or you will be able to focus on it, so no motion blur.
I don't think it should be implimented because it is just like depth of field blur and if we don't impliment that, then, we don't impliment a "motion blur."
Depth of field blur is also extremely hard to implement and shouldn't be done at all, because depth of field is again, just like "motion blur," - it's a loss of focus on an object that you aren't focussing on, only that motion blur is a loss of focus on an object that you can't focus on.
You need Actual depth for this these blur ideas to actually work and I think it would look terrible as it has already been implimented badly.  Unless our eyes do it for us, then there should be no motion blur or loss of focus, because that is not how the world looks.
Video games should be more in tone to create a "real world" and not a movie experience.