Microsoft for two BUILD conferences now has stated putting more weight into Xamarin tooling for desktop as well as mobile (WPF, Cocoa, and Gtk renderers for Xamarin) is an end goal. They exist as community projects already (find them all on GitHub), and it continues to sound like Microsoft only expects to invest in them so much as they find community interests, and maybe a reason we don't hear a lot of people talking about those projects is there sadly isn't enough non-Microsoft community interest in such tools.