There were plenty of nuns in St Peter’s Square when during the entire conclave.
In answer to your question, there were no nuns on the balcony because there was no need for them to be there. The Cardinals are the Pope’s personal messengers and helpers. They are his aids. The Cardinals elected him to the throne of Peter. They were there because they were the ones who chose him. They played an active role in the conclave.
You seem to be questioning the role of women within the Church. Woman are afforded the greatest respect within Catholicism; in fact, Catholicism is the only brand of Christianity which gives the Virgin Mary an exhalted place of honour amongst creation.
The nuns are wonderful people. They teach, guide, help, and provide spiritual care to many people. Nuns receive a lot of bad press these days, but don’t let that fool you. There are some brilliant nuns out in the world today.
However, you should realise that men and women occupy different roles within the Church hierarchy. Nuns do not occupy positions of authority because Christ himself did not appoint female apostles. Despite this, it can be plainly seen that he deeply loved and respected all women, especially his mother and his female followers such as Mary Magdalene.
As Christ did not appoint female apostles, it would be impossible for the Magisterium to permit women priests or women cardinals. It is theologically impossible. This in no way creats an equality between the sexes; it merely recognises that there are different roles for men and women.
Nuns occupy many prominent roles within the life of the Church. Many are educators, and many are nurses, or care givers to the needy. I know some nuns who are the principals of Catholic schools. Even though they are not involved in leadership, they have a place in many other important areas. The Church could not survive without holy nuns.
