Without even going to “single pass stereo”, just having “single pass instanced rendering” would be of great help to lower CPU utilization (especially since folks have been asking for Quad Views), and it’s a standard feature in DX11/12, unlike single pass stereo which requires the use of vendor-specific API and also has a few caveats with certain headsets. You’re much more likely to get them to implement instanced rendering than single pass stereo.