This seems like yet another case of a software company building a prodict that is over specced and not really what customers want.
The old version of Arc Explorer would run on anything and worked well for what it was intended for.
ArcGIS Explorer now requires a high powered machine and will not run on a terminal server. Surely a terminal server is where you are most likely to want to run an explorer type product. You can use Arcmap on a desktop machine.
Are ESRI thinking of bringing out a 2D version of Explorer that will run on remote dsesktop??
Les