Initially, yes - it's way, way easier to port an iOS app to Mac than to port an iOS or Android app to Windows. (our understanding is that a basic Mac port with Marzipan will pretty much just involve checking a box in Xcode and rebuilding) In fact there's a pretty good chance that 4.0 will be out on Mac before it's even out on Android
We might consider a Windows port if the Mac app is a big success, the main question is how we pay for it - we aren't confident that enough people would buy our app on Windows to pay for the cost of that port. We've toyed with the idea of doing it as a Kickstarter, actually - that would be a good way to see if there was enough interest.