The biology is a bit more complicated than that, though. Sure, if we had a big database of all the correlation factors in some easily computer-readable format, standardized testing procedures that lined up with these factors, and an army of experts keeping all of this up-to-date, it would be easy to write a script to make it all work. But we don't, and (in my off-the-cuff estimation) such a project could wind up being of Human Genome Project-esque scale.
Watson is giving us a way of doing this when the available data is in a much less accommodating format (namely, scientific literature.) Not, perhaps, the biggest achievement ever, but pretty nifty and useful.
Actually there are armies of experts keeping this all up to date, and some companies make a lot of money selling this as a service. The name of the role is "curator", and they basically map research to genetic variants, keeping a giant library up-to-date.
Watson is giving us a way of doing this when the available data is in a much less accommodating format (namely, scientific literature.) Not, perhaps, the biggest achievement ever, but pretty nifty and useful.