Guha is not quite the champion of RDF, McCarthy remains the champion of a variety of logical formalisms. Automated reasoning is well documented. It does work for limited domains. In fact, just about anything will work when operating in a sufficiently constrained domain. DKR, however, wants to take on the universe, and everything.
Humans talk in qualitative terms for normal conversation.
IMHO, the game is to invent a KR scheme that lets us partially automate handling of all kinds of representations. This appears to be a highly constrained natural language. Telling jokes with PNL would not be easy, but describing the evolution of an hiv infection would. Daphne Koller at Stanford has developed what appears to be a seamless integration of bayesian and description logics. One of her students, now at Harvard, is adding linguistics to that mix.