Documentary (or not) black and white can never truly be an accurate representation of the situation, we do not live in a black and white world - visually, emotionally or morally. Anything black and white can only be one take on a particular situation, this does not mean that I would rule it out and it certainly has its place. When communicating (particularly) horrific information it is probably the most pragmatic and the least gory way to get the message across whilst minimising sensationalism.
Regardless of how easily we are fooled by our eyes. even when daydreaming, humans are visually voracious and are constantly absorbing visual clues. All of this information is received in colour - even the black and white images - because of the light (natural or man-made), the environment (outside, inside, hot or cold) and finally and most importantly because of our mood. (From my research done for assignment 2 - depression.)
This assignment presents a very limited and distorted view of a group of people talking to a stranger and sharing 'personal' information. I believe presenting these images in black and white would further distort this view.
Changes to the text have a dramatic affect, the image is now the focus but at the same time the information presented is not diminished.