I am new to this; so I may misunderstand, or I may be restating things which have already been said.
The various documents and policies appear to indicate that NPOV is primarily a matter of presenting facts in a fair and unbiased manner. When there are differing viewpoints or opinions as to what are the facts of a subject, then NPOV would require that these viewpoints be presented in a fair and unbiased manner, without undue emphasis -- or undue lack of emphasis -- being given to one or more of those viewpoints.
However, in this case, we are not dealing with fact, viewpoint, or opinion. We are simply dealing with *nomenclature*. While the names of things may well reflect cultural or other bias, it is also true that through long, common usage they lose much (if not all) of the connotations they may have once had.
Does NPOV require that we reject the name of the month of June, because it is based on the name of a Roman goddess?
It is likely that the overwhelming majority of people consider "BC" and "AD" as simply labels -- giving little (if any) more thought to their religious context than they give to the label "June".
It is possible that rejecting a commonly held and accepted nomenclature in favor of one which many would perceive as being artificially neutral could be considered as the violation of NPOV.
It is questionable whether the goals of the Wikipedia project would be well served by taking it out of the mainstream and toward what many would see as an "elitist" stance.
Good luck, Bill