The HC had never been a HC before. The OC had never been an OC before. The DC had never been a DC before. BYU hired them because they wanted to save money despite a huge surplus in revenue.
You can't expect first time coaches to be at a 12th season coach level, especially when there is a learning curve at BYU too. Make no mistake, the coaches need to improve big time. That doesn't mean the roster isn't dramatically better now than 3 seasons ago.
What I see is a coach that invested in younger players, because the upperclassmen he inherited haven't been great. The coach has an extension to play his players as upperclassmen. Some of those young players look like difference makers. This will be fun watching the team and coaches develop.