I disagree that he's a rip-off artist. There is a difference between being influenced by something, and being calculatingly derivative. To me, that difference is a certain confidence in delivery, which I think James Blunt has. I have heard the Buckley's, and quite frankly, I prefer James Blunt.
I mean, let's compare Jeff Lynne/ELO -- highly derivative of the Beatles, to the point of saying that Lynne has a Beatles fetish. Hard to argue. And yet, I don't like the Beatles, and I do like ELO. And ELO has stood the test of time, as well. Maybe not in the same standing as the Beatles, but still widely regarded as a classic band. So...there ya go.
There is no such thing as originality any more. Certain musicians stick their head in the sand and come up with something that they consider original -- and it is, to an extent. As a musician, one has to stick one's head in ...erm... one's sand...otherwise one would lose all interest in making music. The important thing is that it is interesting to you, and hopefully that interestingness will translate to the target audience.