I think most expected the Big Ten to take a reputational step back this season, but, speaking for myself, the measure by which the conference has fallen behind its major conference colleagues is surprising. And while it would be nice to blame this entirely on Rutgers, that simply is not accurate.
Pomeroy Ranking, Top-12 Teams of the Big Ten
2014 Pomeroy Rank
2015 Pomeroy Rank
While the bottom of the conference (read: Rutgers and Northwestern) certainly drags down the average, the fact is that if the Big Ten jettisoned those two programs today, the conference would still be worse than it was last season, largely because the top of the conference is not as good as it was last season.
Obviously, much of the rotation of last year's Michigan and Michigan State teams is now filling out NBA rosters, but that kind of turnover happens every season. I think the bigger issue for the Big Ten was simply that the conference did not restock the cupboard. In 2013-14, there were 14 top-100 freshmen playing for Big Ten teams (this includes Maryland, and technically Rutgers)—of those 14, 11 have returned as sophomores. This stands in stark contrast to the prior year's crop of sophomores: of the 15 top-100 players that stepped onto campus in the fall of 2012 (not counting Maryland or Rutgers), exactly none failed to return to school the following season. Those sophomore leaps helped fuel the Big Ten's supremacy.
That's not the only way to conference superiority, mind you. In 2010-11, the senior-laden rosters of Ohio State, Purdue, Penn State, and Illinois propelled the conference.
The good news is that the Big Ten should be a much more capable conference next season. As best as I can tell right now, the top seniors in the league (in no particular order) are Frank Kaminsky, Aaron White, D.J. Newbill, Travis Trice, and Andre Hollins, with the injured Rayvonte Rice deserving of asterisk status (the fact that he hasn't played much in conference games means that his absence next year places Illinois in the same position it is now). As for early entrants into the draft, only four appear to be in the first round as of now (D'Angelo Russell, Sam Dekker, Jake Layman, and Caris LeVert, though everyone after Russell is borderline/absent in some mocks). I wouldn't dismiss the possibility of an overestimation here or there, scouts falling in love with a 7-0er that can chew gum (Purdue has two of 'em!), or someone like James Blackmon or Melo Trimble playing their way into the first round. All that said, I suspect the vast majority of the early-entry candidates mentioned here make it back to campus next season.
Also, it's worth noting just how good this year's crop of freshmen are:
Conference Games Only
Name, Year of FR season
Walton, Jr., 2014
(Michigan fans—take up the Irvin snub with the Big Ten—I'm merely pulling the all-freshman team)
Last year, precisely one freshman fit the bill of both "go to" and "efficient." This year, that number stands at 5, with plenty of efficient newcomers in less starring roles. Sure, we're only just short of halfway through the conference season, but it's likely this year's freshman class will eclipse last year's by a significant amount.
So long as they stick around for next season, expect the conference to make a respectable run for the top spot.