Ken Niumatalolo was offered the HC job before Kalani. Ken was told that Detmer was part of the deal and he walked.
Kalani had the same deal and agreed, though Detmer was not his first choice. It took a substantial amount of money to convince Ty to come coach, which put severe restrictions on what Kalani could pay the other offensive assistants. That offensive staff was probably the most inexperienced group in the country, so its easy to see why the results were so bad.
The current offensive staff has the experience and now has had ample time to install a system. Sitake has his QB, talented skill players, and an experienced O-Line. I expect we will see big strides this year with a few surprise wins.