Every executive has a different management style and many prefer to let the results accomplished by their employees reflect their managerial skills. As a result it is often hard to judge effectiveness without some fair amount of inside information (hopefully less rather than more fake news).
Agree with your assessment as a former student who has followed ND sports from the 50s actually paying at least passing attention to the ones other than FB, BB, and hockey. For whatever reason the overall sports program has become much better over time with a lot of visible actions since JS took over in July 2008
This report this government required 2016 has a lot of puffery but does detail the state of the ND athletic program at that point and has a lot of history what led up to those results. Seems like a lot of major initiatives were planned before JS but he got them implemented (includes new "digs" for the fencing and hockey teams plus a renovated BB facility). BTW the PDF file at the top of the report has a lot of stats about specific programs.
http://www.und.com/ot/eada-report-12.html
Also realize that to many the only job of the athletic director in the current way ND is organized is to have not just a winning (aka "good") FB program but to have a BCS contender every year whereas think it is much more about maintaining and ideally increasing the FB revenue stream - seems like JS as done that fairly well but again without inside info ...