More pro-active change in direction from the top is part of it. Testicular maturation, let's call it.
That, and one of my most painful observations from last year was that safety play was flat-out lacking. This in turn affected corner play if big plays were to be contained, and that affected game planning by the DC. You can't man-press effectively if you're forced to hold it for long if you have no safety help over the top.
Jim Youngblood 53 pointed out in great detail how the planning worked.
I said something a time or two about safety play; but soft-pedaled it because we started without Fuller and the new guys thrown in were over their heads. We were 2 or at times 3 deep in the depth charts at safety positions. That's never good.
This year we have Fuller at full steam, Yeast and Lake swimming well after their total baptism (some of it by fire) last year, and JJIII back in the fold. We're good. That frees up the CB's to make plays rather than prevent catastrophes.
The coaching changes are great - and this year they have more pieces on the board to play with than last year. It all works together and it's effective- ask DK Metcalf.