This RFE is specifically targeting how to represent nodes on Cray X-series systems. (@djohnpbs -- perhaps the Summary could be changed to include "Cray X-series" to make this clear here and in JIRA?)
This RFE was not intended to change functionality on generic Linux nodes nor for SGI UV -- PBS Pro should continue to support one vnode per NUMA node on generic Linux nodes and SGI UV. (On UV in particular, this is allows the PBS Scheduler to leverage placement sets for better, and more predictable, application performance.)
From the discussion so far, it is clear that the default (on Cray X-series) should be "one vnode per compute node" (and not "one vnode per NUMA node").
Whether there are any actual users of PBS Pro that depend on "one vnode per NUMA node" on Cray X-series is still an open question in my mind, as nobody has put forward even one case of anyone depending on this configuration, nor any examples of capabilities that could not also be achieved under the "one vnode per compute node" configuration.
If there is a compelling reason to support "one vnode per NUMA node" configurations on Cray X-series, then I propose not inventing a new name, but using the same name as Cgroups hook for the setting: "vnode_per_numa_node". (It's bad design to have two different names for the the same thing.)