I've read some of the NFL scouting critiques of Trey Smith and the "coaching" he received. This is a guy who has likely lost 7 (possibly 8) figures from his first NFL contract due to the coaching he received. We've seen it with other players at that position (Mays, Wright, Morris). JGs fundamentals got worse each year. I've coached elementary school LBs who take better angles than our team did last year. You layer 3 to 4 assistants who were in over their head, plus a HC in over his head, and outdated offensive and defensive schemes and you get what we saw last year.
I'm not sure Heupel will be the answer but I know it's going to take a while to fix the fundamental and schematic mess he inherited. Thankfully for us, outside of the Big 3 games on our schedule, we should not be at a huge physical disadvantage in the 9 remaining games....