There is a nice talk by Levoy. He is trying to build a motion camera:

Why is Sports Photography Hard? (and what we can do about it)

http://research.microsoft.com/apps/video/dl.aspx?id=146906

So for sports photography it seems very useful. Replacing the green screen doesn't seem to make sense.

For macroscopic objects depth reconstruction with two cameras like in the Kinect seems the better alternative.

Object excemption seems to be a nice idea. I can't remember having read anything about this. In principle it should be possible to recover an unsectioned stack of images.

One can then use an iterative algorithm to subtract in-focus information from on slice of the stack from each of the other slices and end up with a deconvolved image of sectioned images.

Then one could delete one object in the stack and recalculate a superposition of blurred sectioned images to recover a reconstruction representing the object without the image.

This is quite complicated. Just imagine to remove a wine glass from a scene. One needs to delete all the rays that went through the wine glass and bend them such as though the wine glass wasn't there.

One can argue that polarization and absorbtion effects will be very hard or even impossible to handle correctly.

Certainly light fields contain A LOT of potential.