When Bronco realized he could recruit more talented LBs than DLs, he switched to a 3-4 front.  Remember, he orignally went with the Rocky Long inspired 3-3-5 (but we didn't have the DBs to pull that off).  I think KS would like to replicated what Utah has been able to do with a very stout front four.  We may not have the players to do that year-in/year out.  Besides, you should always adjust your scheme to your personnel.