Let me preface this by saying that I feel like I am often relating things back to his days at UC, but I'm a local guy and UC has always been my no.2 team so it's what I know...
I think the answer to your question is both. It's obvious that some leadership needs to step forward... you know what you're getting from veterans like Zack Martin, TJ Jones, LNIII, Dan Fox, Bennett Jackson, or even Ice Cold Tommy Rees. Those guys will be leaders. But all of these guys will be gone after this season, so I believe BK is pushing for plenty of "younger" guys to step up and be prepared to answer the call when the time comes.
Where my knowledge of his time at UC comes into play is the fact that he was constantly rotating fresh legs in everywhere, with the exception of QB and OL. He didn't have the OL depth to do so, but he had no problem playing "less-talented" WR, DEs, DTs, LBs, or DBs as long as they were fresh. You can see it with his use of the running backs; even if he has a "work horse" on hand, the ratio of carries between running backs will almost never show a "work horse" because of how much he values fresh legs to go along with his "big chunk" mindset. A guy may be a work horse, but fresh legs are more important when you are trying to produce chunk yardage. A work horse may get five yards every play like clockwork based on talent, but a less-talented player might produce carries of 10+ simply for being fresh. That's what BK wants.
He platooned his WR's for the most part when it came to involving guys behind the top two, something we haven't seen much of at ND (unless I'm missing examples) due to a change in offensive philosophy (less 4 WR sets, more TE on the line). At UC he had guys like Dominick Goodman, Mardy Gilyard and Armon Binns at the top (which I would say is the counterpart of Floyd, Eifert and Jones), but 4 WR sets were used often enough that 4-5 guys would all share the 3rd/4th spots in the rotation. Certain WRs need to be weapons on every play, but the other spots have a premium on fresh legs because they aren't being covered by the oposition's lockdown defenders anyway. It seems like common sense to me, but you often see coaches get locked in to a mindset of "this is the depth chart, this is set and the way it will be unless someone is hurt." BK isn't like that, so I believe he really is banking on being able to put almost anyone on the field at any time in an effort to outwork the opponent, especially if we are going to see an offensive "grind it out" style of play.