I'm not sure what the hand wringing is about concerning the F-35 HMD. All the 4+ gen aircraft (basically any aircraft that has HOBS missiles) already have HMDs. The procedures and logistics are already in place to issue, fit, maintain, service, calibrate, etc etc such helmets. The F-35's HMD is just a further development of this already well established concept that enables the elimination of the HUD. Why is this so terrible? What am I missing?