I think it's less of a problem at NU where freshmen coming in are pretty bright and can handle the academics while playing as freshmen. Remember that Fitz also considers more than just their athletic ability when he decides to redshirt a player...factors like how well they have adjusted to being away from home, their ability to learn quickly, etc.
I think it would really suck for basketball players who oftentimes come in more competent at their game than their football playing classmates. They don't have the physical maturity issues and the physical demands placed on them that freshman football players might have.
Yes, it would definitely hurt the Big Ten in recruiting! No, NU will not get any benefit from this because precocious players will go to other conferences. NU should want freshmen to play and strive to land more kids who are freshmen ready.