Widger,
I think I'll have to claim those two house points in this instance. I find it interesting that the USMC considered the (non radar equipped) AV8B to be a "day only" capable warplane. The addition of a radar in the Harrier II Plus was considered essential for night ops hence the upgrade. Air to air capability was a bonus and only exploited by the Spanish and Italians.
I'm curious that the RAF does not consider radar to a requirement for carrier borne aircraft when every naval aircraft for last 50 years has carried it. Opinion seems to be divided. The RAF says that radar is not necessary all the other operators say it is. Which is right?