According the designers they considered it, but finally decided to concentrate on the question answering. OCR for this situation could probably be done in fast and reliable way, so it wouldn't make much of a difference. Speech recognition would be harder and less reliable, but redundant most of the time (though it presumably could have helped for the 1920s question).
Understandable, and I agree that they definitely tackled the meat of the problem. I think there could be some interesting problems in the computer vision aspect of it, though. Seeing and interpreting the board is subtly different than a straight OCR problem.
