For me killer features would have been -PCI pass trough, higher and better performing 3d driver, better work with hardware disks - that feature never quite worked on Windows at least. Remote/connect/management and so on - they are nice to have.
These features may have been prohibited by corporate management for some reason since ESXi have passtrough. And yeah - I view it from strong power user/developer/gaming angle, not sysadmin.