This is pure homerism.
Your BIG Metrics that BC "loses" to UConn on:
- State Flagship: no evidence this is a metric. Again, Northwestern, MSU, Purdue and ND in this example. Theoretical advantage to UConn.
- Market Size: UConn barely adds anything to NYC when compared to what BIG already has with Rutgers, UM, OSU, Penn State (and theoretically ND). UConn adds an extra 2% compared to what BIG already has in NYC. It's redundant. UConn only really "adds" CT. BC definitely adds Boston, likely adds all of Massachusetts, and possibly adds NH, VT, ME and RI to automatic BTN carriage. Clear advantage to BC.
- Geographic Presence: 100% wrong. If the BIG adds UConn they would be adding 1 of the 2 New England P5 teams. That's a split of New England. If the BIG adds BC -- and UConn gets passed over by the ACC, which is very possible -- the BIG adds ALL OF NEW ENGLAND. They would be the only major college football team in New England. Clear advantage to BC.
- Athletic Success: BC wins football and hockey. UConn wins basketball. The other sports are a wash. Advantage to BC.
- Facilities: BC just pledged $200 million to facilities. If this really became a debate you'd see BC pump out renderings and make unequivocal BC's committment to athletics at the highest level. Also, BC with facilities on campus...in the city of Boston, where all of the other BIG schools have large alumni networks that would love to go to games more often. Advantage BC.
- Fanbase: I don't know what you're basing this on. In football BC (outside of really rare and random 2-win seasons) draws more fans to football games, draws better TV ratings, and commands more national attention. You have basketball. I guess you can hope they care about basketball fanbase. Advantage BC.
BC is not "a nice undergraduate college in a major city." Boston College is an elite university and a nationwide brand name.
As for Notre Dame, conference politics is a very real consideration. It's not unreasonable that if an independent minded and proud university like Notre Dame was to join the BIG they wouldn't want to be the odd-ball small, private, Catholic school that gets bullied on conference issues. It's not unreasonable that they would insist on a like-minded partner institution to increase their clout in their new home.
Just my $0.02.