Because ArcGIS Online (AGO) is still beta, there are tons of plans to continue adding and fixing datasets. ArcGIS Explorer “piggybacks” AGO so AGX users will want to keep an eye out for the following improvements.
- high-resolution 1 meter imagery for the USA
- detailed street maps for North America and Europe
- USGS Topo Quads
- provincial level political map for the world
ESRI also has plans to improve the existing layers as they get feedback so make sure you let them know in the forums any problems with the labels or data layers.