The blog post makes me quite nervous. It looks like this is a back-door way to remove Explorer Online.
I hope Explorer Online is not going away. I use it in university classes that I teach and for which I provide support. The query tool and presentation feature are unique and make this a much better introduction to ArcMap than the standard ArcGIS.com map viewer.
I'm right in the middle of working with several faculty members on "GIS enhancement" to their non-GIS, non-Geography courses. Explorer Online is a central tool for us. I need to know whether it will be there in the future or not.