From a football perspective, I agree that SB Schools as a whole are definitely one of the weaker links in the NIC. That being said, they are also some of the most competitive schools year in and year out in Basketball, Track, Swimming, Wrestling, Baseball, and even Cross Country.
As a complete conference, there is little reason to see a team like New Prairie or even Mishawaka leave the NIC, (and from what I have heard many parents and boosters are not happy with the travel times and loss of rivalries). If Mishawaka had stayed, and you have the new Elkhart School, the NIC north would be as good as almost any conference top to bottom.
The question is, how do Glenn, Jimtown, Clay, Washington, and Bremen consistently compete in more sports.