Would be very useful if I could see the linkage between the binding of individual properties and what is bound to the data context.  For example, I need to be able to position the cursor at a binding of a Text property of a TextBox and press F12 to see the class/property the binding relates to.

Sure, the specific bindings are not known until run time. And can vary even then. But the majority of the time bindngs from XAML will not change. Possibly if run time info could be captured. "The last time the app was run, the XAML of a specific window class had its data context bound to a specific object type".  Then the editor could access the historical info about the running of a window class to see the type an individual binding is likely binding to.