A. Ahhh, you are very perceptive! First, let me address changes with the new translation, which was implemented in 2011, and then address the addition by Pope Francis.
When the Liturgy was translated from Latin into English and other languages, this was the first time in the Church’s history (int he Latin rite) that the Mass was celebrated in a language other than Latin. When that translation took place in the early 1970’s, the group entrusted with the translation, the International Commission on English in the Liturgy (or I.C.E.L), had to do their work without any clear guidelines. Everyone involved in the translation no doubt did their best, but still, it was the first attempt and was done quite quickly.
Over the years, many began offering new suggestions and ideas for a better way to translate the Liturgy from the Latin. Pope John Paul II, in 1997, issued a document in which he set down some new guidelines on how to translate the Liturgy. Generally speaking, he asked that translations be more exact, rather than paraphrasing the Latin content. This started a long process of evaluation, study, conversation, consultation, and re-translation. This time, the Church wanted to set forth a translation that everyone agreed upon. Every bishop in the English-speaking world was consulted, as well as many scholars. They simply wanted to get it right. The result of this very long process is, what I believe to be a very beautiful and elevated English translation of the Mass. All of the hard work over many years paid off!
As for the addition of St. Joseph’s name to all of the Eucharistic Prayers, this is something quite different. This was not a matter of determining the best way to translate the entire Liturgy; rather, it was the matter of expressing our devotion to St. Joseph in all of the Eucharistic Prayers, rather than just one of them. In 1870, Pope Pius IX proclaimed St. Joseph the Patron of the Universal Church. The Vatican’s decree says that St. Joseph “stands as an exemplary model of the kindness and humility that the Christian faith raises to a great destiny, and demonstrates the ordinary and simple virtues necessary for men to be good and genuine followers of Christ.” In 1962, Pope John XXIII had St. Joseph’s name inserted into the Roman Canon, which is the first Eucharistic Prayer and the only one in use at that time. For some reason, when the three additional Eucharistic Prayers were made available in 1970, they did not contain St. Joseph’s name as the Roman Canon did.
Apparently, Pope Benedict XVI had received many requests from throughout the Church to insert St. Joseph’s name into all the prayers, just as Pope John XXIII did back in 1962 when he inserted St. Joseph’s name into the only Eucharistic Prayer in use at that time. Pope Benedict XVI ultimately approved of this, right as he was stepping down as pope. Pope Francis quickly acted on Pope Benedict’s desire and made this a public decree. In a sense, you could say that this process started in 1962! Therefore it was a much longer process than the re-translation of the Liturgy, which began in 1997 and was implemented fourteen years later.