O.k. let me make this simple. The Roman use of Hail was reserved for Caesar and those recognized as Caesar's envoys, the same with purple clothing.
Also, Nazism taught that there were to be Three Reich's. The First was Rome under Caesar.. The Second was the Holy Roman Empire. The Third was the Nazis, and they taught it would be an eternal empire. It was believed by the SS, the Schutz Staffel, that Hitler was destined to bring about this empire. It's why Nazi law enforced that all SS, and eventually all high ranking officers of the Wehrmacht made oaths of allegiance to Hitler directly and denounce any religious affiliation. They were also required to salute and exclaim, "Heil Hitler", an homage to the Hail Caesar.
Now, the majority of translations and all of the ones I've read from KJV, NIV, NRSV, NAB, NKJV, NJB, Sainte Bible (French), and Doeuy-Rheims have all translated the phrase to "Hail, full of grace." Take it up with those translators.