Sirmon maybe awful, but it is impossible to tell if he is awful because he can't coach or he doesn't have talent or it is combination of the two. The sample size is too small. They were terrible at Miss St well Miss St isn't exactly wearing it out against good teams either with Louisville's old coach.
Recruiting matters. Louisville is starting a true freshman at middle linebacker, at corner, and occasionally at free safety. The truth is they aren't ready. They are going to be good, but they aren't there yet. They have no legit backup for Stacey Thomas, Avery another true freshman will play a bunch and he is 210 pounds as a true freshman. FYI a position he has never played. If Grantham was so good why is Louisville having to rely on true freshman? They have no legit pass rushers after 3 years of recruiting. All the comments talking about how talent is an excuse, it directly impacts what a coach can do defensively.
The complaints about tackling, poor execution within the system, not being a physical defense and lack of effort are a legit concerns. That is on Sirmon and his staff. I am not convinced you can coach defense without someone on staff providing energy on the sidelines. Defensive is about energy, emotion, and playing fast I don't see that kind of energy with this staff. You need a Grantham, Bedford, or someone in that mold to keep the energy going.
That is an overall concern for the entire program. Petrino said it if you need me to get you going that isn't him. I think that is a very pro approach, but he has to have someone on staff providing that energy. His brother was that guy the first go around.