WSDL 2.0 - First impressions

After reading Dave Orchard's Blog: WITW WSDL 2.0 HTTP Binding I downloaded some of the WSDL 2.0 specs to read on the train. I am pleasantly surprised as compared to WSDL 1.1 it appears much more accessible. Whether my positive impressions are due to too much reading of WSDL 1.1 not sure. Mark Baker as always has a very pithy comment that aside all the people involved should be congratulated for their hard work.
Congratulations aside, I question the idea of a "single SDL to bind them all". So I ask the question, why do we need a single SDL, when would I need to use both? It is certainly a nice idea but as technology evolves, different areas typical move at different rates and evolve in different ways. Linking them usually tends to be a bad idea.