I'm going to go out on a limb and say that I think multi-touch is worth a patent. I'm not sure if Apple is the one that deserves to hold it (I'm not sure what the prior art is on it), but it is THE THING that made the current crop of tablets and smart phones possible. To me, it seems non-obvious because if it was so obvious, why did we have to endure a decade of shitty unresponsive stylus interfaces?
I am not sure they could get it depending on the dates because the "preliminary" version of the surface tablet was the multitouch surface table by microsoft in early 2007