I don't really think we needed to expand at this point, as it seemed like most reasonable options were off the table, and if we were going to, I think we could have done better. However, academically, it's a neutral, as our lowest school academically that isn't a recent addition is MSU at 75 nationally or so, and both Maryland and Rutgers preserve that, as well as having decent research budgets, etc. Athletically, New Jersey actually no longer has any pro teams in the state, and Rutgers is the biggest game in town now (not saying much, I know), but if they get better/play better opponents, maybe they'll make this good. Maryland seems to be on the upswing in basketball again, and who knows with football. With secondary sports like soccer and lacrosse, they'd jump to the top of the conference automatically.
Another hidden benefit is that with Maryland leaving, other schools like FSU and Clemson might want to jump the ACC, which could send it into a tailspin, leaving certain members the B1G might actually want like UNC/Duke/UVA/GT open and unattached, which could be strategic. Then again, it might just stop where it is for now, and it just seems weird.