Seven readings aren’t required; however, it makes for a fuller celebration when they are used. Even without the seven readings, the Mass from St. Peter’s was fairly long. You also need to consider the Holy Father’s age. I believe that a much, much younger Joseph Ratzinger would have been able to have the stamina for seven readings, plus all of the other rituals that go along with the Easter Vigil. However, since Pope Benedict XVI is pushing 81, a certain degree of leeway and prudence comes into play.
Furthermore, the ceremonials were fairly lengthy. Not only was the Exultet (long form) chanted, but, Pope Benedict also had five folks he had to baptize and confirm.
Now, since I didn’t see the broadcast from the National Shrine, I couldn’t tell you the possible mitigating factors. However, as far as a time limit, I don’t think such an animal exists as far as EWTN is concerned. They’ll carry the broadcast until the feed from the Vatican stops.
