It would be great if there was a Linux build (for some flavor or another of Linux - Centos, Ubuntu, whatever). Why?
It would save us the cost of a Windows license (thus lowering the barrier to entry)
It would inevitably be more stable - my Windows 7 box tanks almost every ride ( in addition to Zwift crashing - this is being dealt with on a support ticket already).
Given that you’re already cross compiling for a Linux/Unix clone in the form of OS X, it should only be the UI layer that needs a port.
Although, now that I write this, perhaps the larger Zwift audience isn’t going to be that tech savy, so linux builds would be for a limited few, thus of a low ROI for the Zwift team.