One of the guiding principles of Roon is that users should have the same experience across platforms. There are some exceptions, the iPhone app doesn’t have everything that other Controls do, but the devs aim for a uniform user experience. So my guess is that Roon itself is unlikely to add widgets, as that would create a point of departure from Android, PC, and Mac Controls.
BUT, release of the Roon API is coming with Roon 1.3 and that will enable all sorts of user or third party defined functionality. I don’t know enough about either widgets or the API to say how they might interact.