Since the Flutie years, BC has changed dramatically. BC has become a very good school, but they used to be a local/regional school and they are now a national school as the students come from everywhere. In the old days, BC was full of local Boston kids, especially kids with Irish backgrounds, but those days are long gone.
Many like how BC has changed, but local alums aren't so happy with the transition as it is now very hard for local legacies to get into BC.
Why is this important? BC has lost its connection to the locals as they have become a national university. They probably can't grow local athletic fan interest that much going forward given that they aren't focused on the local market anymore and attending athletic events at BC is very difficult, especially for the casual fan.
BC is a good fit for the ACC which has similar mid size private schools like Miami, Wake Forest, Duke, and Syracuse, but all of these schools have fan base issues. Growing their fan bases will be difficult as none are state flagship universities.