Unless you are a scout, there is really no way to evaluate High School "talent" without using the rankings "professionals' assign them. If you think UC and ND were recruiting talent of the same "grade" then I don't know what to tell you.
Further, if you think high school players can't be made better or fail to live up to their potential due to the quality of coaching they receive, then I don't know what to tell you either.
Notre Dame's defense had athletes. Strong, fast, big, etc. They just didn't do things fundamentally well, they weren't put into schemes to succeed and they were soft. Saying that an Kelly-coached Notre Dame would get destroyed by a Kelly-coached UC is ridiculous.