My observations with Big Ten fans is that Maryland and Rutgers were ultimately acceptable because (a) they also added a school that actually draws football viewers (Nebraska) and (b) there's a greater understanding of how the BTN makes money with cable households compared to when the Big Ten first announced that it was exploring expansion 3 years ago. To be clear, though, (a) is extremely important. For a move to be popular with fans, there HAS to be a school added that such fans will want to sit down and watch their teams play football against. There's already a bit of consternation about how the Big Ten West schools are going to be playing Michigan, Ohio State and Penn State less often, so to the extent anyone else is added, they had better make it worth seeing those 3 schools even less. A pure market grab without a marquee (or at least upper tier) football brand will not pass muster with the fans for future expansions. This also isn't irrelevant to the financially-minded powers that be, either, as a powerful football brand is still the proverbial golden goose that makes the market-based riches from the BTN possible. Believe me - they're not oblivious to this. (Now, I know that the retort to that is that Rutgers and Maryland are historically terrible at football, but as I've pointed out here, New Jersey and Maryland are the two best football recruiting states in the North that aren't already in the Big Ten footprint, so there IS a very direct football-driven reason for those additions.)
The AAU issue is what ultimately matters the most for the Big Ten, though. I'm not saying that is the correct way for the Big Ten to expand (as I've personally argued for them to grab Florida State), but that is certainly how the powers that be in the Big Ten are approaching expansion. Close or "having a plan" isn't good enough - if you're in the AAU, then you have a chance, but if you're not in the AAU, then you don't have a chance. It's as simple as that (unless you're Notre Dame, in which case all expansion qualification rules go out the window if they're dropping football independence).