I don't think Benedict XV was uppermost in Ratzinger's mind in choosing his name, though it may have played some role.
I would imagine his choice of name has far more to do with St. Benedict, patron of Europe, patron of the re-conversion of Europe. Ratzinger's greatest concern is the effort to obliterate Christianity from Europe, to deny it any standing whatsoever in the E.U. If that trend is not reversed, the day will come when the bishop of Rome will once more be crucified in the Vatican Hippodrome (figuratively or perhaps even something approaching literally).
Ratzinger has written extensively on this "culture wars" theme. He does so from a European vantage point, but with globalization, it is an issue for everyone, even in the Third World. The exact way these culture wars play out differs in Europe and the United States and Latin America and Africa, but the principles are the same and Ratzinger has thought about them long and hard.
I agree with that. but, given his age, I just think Ratzinger's focus is going to be on the Church, and not on the wider world. Clearly the cardinals wanted a transitional papacy.
Does Ratzinger speak English?