Mil spec also determines minimum SNR and Halo, resolution, cathode sensitivity. Different mil contracts have different spec. Omni VII is highest spec, iirc, Omni VIII is current, with slightly reduced minimum SNR.
Some guys can't ignore blems, some can. Many blems which seem really apparent when looking at a white wall disappear in actual use. Significant blems in a scope would be a lot mote tolerable to me than blems in a PVS 14, so long as the blems don't encroach on the reticle.
JPK