I don't know if porting is that straightforward (it is a removed barrier, though), but as someone that spends most of his time in a non-Windows OS, I would adore to have Paint.NET on my OS.
If a native version isn't possible, perhaps emulation (via Wine, Crossover, etc.) will be easier to achieve in the future, which would be a good middle ground between running a virtual machine and having a native version of the software.