I think its Stanford plus Atlantic exposure. The more national the conference can be, the more tolerable I think it would be to Notre Dame. Adding in annual rivals Stanford and USC is also helpful. Only Navy remains an OOC game.

So which 4 schools from the ACC?

Ideal would be Georgia Tech, Miami, North Carolina, and Virginia. I'm not sure which direction these schools would go if both the B1G and SEC made the offer. Institutionally, these are better B1G fits so let's go with that. The SEC then grows to 20 with Clemson, Florida St, North Carolina St, and Virginia Tech. The XII brings in Duke, Louisville, Pittsburgh, and Syracuse for 20. Boston College and Wake Forest go independent and park their non-football sports in the Big East. Oregon St and Washington St join the MWC. California goes independent and joins the Big West for non-football sports.

FBS Power 2+1

B1G
Georgia Tech, Illinois, Indiana, Iowa, Maryland, Miami, Michigan, Michigan St, Minnesota, Nebraska, North Carolina, Northwestern, Notre Dame, Ohio St, Oregon, Penn St, Purdue, Rutgers, Stanford, UCLA, USC, Virginia, Washington, Wisconsin

SEC
Alabama, Arkansas, Auburn, Clemson, Florida, Florida St, Georgia, Kentucky, LSU, Mississippi, Mississippi St, Missouri, North Carolina St, Oklahoma, South Carolina, Tennessee, Texas, Texas A&M, Vanderbilt, Virginia Tech

XX
Arizona, Arizona St, Baylor, BYU, Central Florida, Cincinnati, Colorado, Duke, Houston, Iowa St, Kansas, Kansas St, Louisville, Oklahoma St, Pittsburgh, Syracuse, TCU, Texas Tech, Utah, West Virginia

B1G is good now!

I do think Notre Dame helped show B1G the "($) Green Print", play national schedule on TV every week!

I also think the BIG will need to keep the division-less football model. The Flex Protect Plus approach to scheduling will allow ND to still have a national schedule with rotating teams. Lock in USC and Stanford as your protected games and ND gets to end each year in California.