Kirby (to his credit) hit a sweet spot with a very "mature" QB in Bennett who was in his mid 20's, along with having a dominant front seven. Neither of those are there and it was evident this season there had been a dropoff.
As you've stated, "we'll be fine" and once CKD gets his offense in place Kirby is going to go through some defensive coordinators trying to find an answer to our offense.
The PC went well I thought. If you’re looking for more CKD content, there’s some good stuff on youtube from his tenures at Sioux Falls and Fresno. Great hire!