The Eastern Sports Conference would have included
Penn State, Syracuse, Pitt, West Virginia, Boston College, Army, Navy, and Maryland.
Ironically Maryland would have been easily convined to join the East in those days as the school had great football rivalries with Penn State and WVU.
The Big East would have replaced Syracuse and BC with a school from Boston (possibly Boston U or UMass). Since Pitt was not admitted at the creation of the Big East, the Pittsburgh market would have been left to the all sports conference.
Big East today if Eastern Sports Conference formed:
Saint John, Seton Hall, Villanova, Georgetown, Providence, UConn, UMass or BU, St Bony or U of Buffalo.
Lash, I think you nailed it with the Eastern All-Sports Conference. Maryland certainly would have been torn, & it would have been interesting to see if they could have been wooed. Historcally, football had been very important to them, but by the mid-80s they were also big time bb in the ACC mold. Maybe their frustration at never being able to beat out UNC in ACC hoops would have been a catalyst to move them to such a conference as much as their rivalry with Penn State in fb. I think that Rutgers would have been part of the mix as the State University of New Jersey & because of their academics, their facilities, their proximity to NYC, & because of their bb, which had been top notch in the decade leading up to the mid-'80s when these decisionswould have been under consideration. I also think that Temple would have gotten some consideration. I'm not sure about Army & Navy, but you're probably right.
One of the things that gets lost in discussions of the old Big East is how important facilities were to their blue print. ESPN came along after the conference was founded, so as important as they were to the early success of the conference, they were not an important consideration in the original blue print. However, downtown arenas were enormously important to the conference & they sought schools that had the capability of selling out such arenas (12 - 20K). Oddly enough, it was the 2 football schools that were the exceptions to this - BC & Syracuse - although BC had access to the Boston Garden for a really big game. Syracuse had the largest on-campus arena in the region in the old Manley Field House & within a few years, the Carrier Dome was more important than any downtown arena
It was the Providence Civic Center, the Hartford Civic Center, MadisonSquare Garden, The Meadowlands Arena, the Spectrum, & The Capital Center that were the crown jewels. I think that any attempts to replace BC & SU would have followed this same blue print. Unfortunately, I don't see any schools at the time that had access to major civic arenas & had shown the capability of filling them up. Holy Cross was an original invitee & had access to the Worcester Centrum, but by the mid-'80s they were moving to non-scolarship sports. The BE already had all of the major arenas locked up otherwise, so I don't know if they might have considered a 2nd NY school like Fordham or a 2nd Philly school like Temple if the latter was not invited to the all-sports conference. St. Bonaventure is too far from Buffalo & I don't think that they would have seen Duquesne as a viable competitor to Pitt. UMass never showed much inclination to play in Springfield the way UConn did in Hartford even though the distance is about the same. (I also think that UConn would have opposed their membership because they wouldn't have wanted the competition for their own at-the-time precarious program.) I don't see BU because they had always been a hockey-first school.
So, I tend to think that they either would have stayed at 6 - a perfectly acceptable number in those days - or that their path may eventually have found its way to DePaul & Marquette just as it has now. These 2 schools best fit the profile of the other BE bb schools, had successful programs that were selling out downtown arenas, & were in positions of prominence in major cities because the state university is located some distance away. The biggest obstacle would have been the mindset of Big "East". It might not have gone "Midwest" in those days. I think that another possibility at the time may have been Richmond, which had an up & coming program in those days, had access to the Richmond Coliseum, and had developed ties with the Northeast through its membership in the ECAC. Another school which fit this mold was Old Dominion, a strong bb school at the time with access to a downtown arena in a large metro area.