you say, doesn't Advent start in late November? For most Western
churches, yes, it does. But as many ecumenical worship leaders have been
noting for a number of years now, including at GBOD,
the readings in the Revised Common Lectionary, and in fact lectionaries
before it stretching back before the tenth century, actually start
Advent readings right after All Saints!
That's because until
Pope Gregory VI changed it in the 11th century, the celebration of
Advent in the West was a full seven weeks, paralleling Lent. Like Lent,
Advent was also a season for preparing persons for baptism and penitents
for readmission to the full fellowship of the Church. While Pope
Gregory VI shortened the season, officially, he actually did not change
Celebrating a full seven weeks of Advent helps congregations regain a strong focus on the actual primary point of Advent (celebrating and preparing for the culmination of all things in the second coming of Christ!). It also helps us to use the readings we already have for the purposes they were originally gathered.
A longer Advent starting earlier, even if not for the entire seven
weeks, also takes a lot of the pressure off of the "December
Advent/Christmas" wars many of our congregations have experienced.
The Advent Project website
provides solid research and an ever-increasing array of resources, for
free, for congregations interested in starting an Advent restoration
project themselves. Be sure to check out the testimony of a United Methodist congregation that has been doing this for several years now, and how they've adapted the model for their context over time.