They've only got 10 rostered (if we keep counting Corson), and of those ten, only 3 are in the top 100 picks (Corson was the #25 overall) and another one was the 100th pick.
And in his two years here, he's got 45 points in 66 games w/ 57 PIM. Had a bit of a touch on the PP though, 8 of his 15 goals came with the man advantage.
Other B1G NHL prospect counts:
MIN - 14, 6 of those are top 50 picks in their drafts (highest is a #3 overall)
MICH - 12, 5 of those are top 50s (highest is a #4 overall)
MSU - 4, no top 100s
PSU - 2, no top 100s
ND - 9, 2 top 100s
OSU - 3, 2 top 100s
So a bit of a talent disparity b/w Minnesota and Michigan - but probably on par with rosters cycle under Eaves and Sauer.
But yeah, the fact that this collection of guys can't consistently beat anyone (barring the season they had the best player in the country and the #1 line in college hockey) is (and has now been) an indictment on Granato.
As an aside, the inclusion of Az State has really changed the landscape. They've not seen success yet, but they're collecting talent that would have gone elsewhere.
That and leaving the WCHA has proven to be disastrous for Wisconsin.