Well, I certainly hope it’s more than just a buzzword, as it’s a profession I’m hopefully headed into!
I think there’s potential for interaction between service design and systems engineering which could make it more than just a fad. There are facets of systems engineering, like this grad program at MIT (http://esd.mit.edu/hse/default.htm), which look at complex systems involving people, not just infrastructure. I think the fascinating part of service design is that it’s geared at making life - perhaps the mundane parts of life - easier for us humans.
If you haven’t already, definitely take a look at my interview with Reboot’s Panthea Lee from Core77’s front page: A Better World By Design: Spotlight on Panthea Lee of Reboot - Core77