"Programs tend to assume isolated use of dedicated hardware, so they have to resort to creating ludicrous numbers of virtual mainframes rather than letting the programs coexist" ----> Sounds like Windows VMWare/HyperV deployment justifications. :)

There is a supposed higher security in zOS partitioning -- but I have no idea what EAL Levels really mean: http://en.wikipedia.org/wiki/Evaluation_Assurance_Level