GMIC is an image manipulation toolkit. Among its various tricks, it can do image inpainting which would give better looking results than the current black box system.

Example: http://cimg.sourceforge.net/greycstoration/img/res_subtitle.png

Of course, the program needs a mask to hide the relevant part of the image, and this is definitely more computationally intensive than adding a black box, but it could be worth it.

http://gmic.sourceforge.net/index.shtml

I think Image Inpainting software at this page provides better result: http://sourceforge.net/projects/imageinpainting/