I didn't think anything needed to be changed on the ZX1 either until I tried the new beta of the Sony music app for Xperia on my phone. I do wish some of those music player features were available on the ZX1, but that would be just making the app compatible with it or updating the ZX1 app. No need for system software update. I will only think the system software needs to be updated if my music streaming apps quit working on it for some reason.
I have no major complaints either, although I would like to have improved playlist management capabilities, and maybe to be able to facilitate hi rez digital output from 3rd party music apps. Whoa, I guess I did have a couple of complaints!