Hmm. Looking at that post, it’s a pretty good quick overview of Cesium itself, but not much related to Google Earth. The last paragraph does say “the next tutorial in this series will introduce the major concepts in Cesium and how they differ from the GE plugin”, but obviously that next post doesn’t exist yet.
Off the top of my head, I would suggest a feature comparison table to give a high-level overview of the differences, followed by a more detailed API/task equivalence mapping (ie, “If you were using a LineString to draw a line, try using a PolylineCollection”). Beyond that, perhaps something like Cesium translations of the Developer’s Guide and the Samples sections of the GE API site. Also, finishing up KML support would obviously be a huge deal.