Unfortunately, I don’t expect an improved DrC# in the near future. We don’t have the funding and personnel to work on such a project. We already have trouble maintaining the DrJava Plug-in for Eclipse.
It may be possible to integrate a C# command line compiler into DrJava, though, if there is interest. There are problems with this approach, though: The syntax highlighting wouldn’t be right, and the Interactions Pane wouldn’t be functional.