I think some of that is more time in the system for players. I think some of that is better players. And I think some of that is more experience for Tuiaki himself. Either way - I like the trajectory even if I don't love where the defense has been the last couple of years. They haven't been great - but they haven't been the reason BYU is losing games. (Or, maybe better said - not the only reason.)
And there haven't been that many games lost in the last couple of years to complain about.