Realistically I think fans of those genres will be sticking to the current approach of using a PS3/XBox pad on their machine. Valve may have to sell a 1st-party knock-off of such a controller just for completeness.

This device is for Valve's massive library of PC games that need a keyboard and mouse that are normally unplayable in the living room (unless your living room includes a desk, in which case it's not really a living room now is it?)