That worst season thing doesn't mean shit because teams that are dominant can become shit (see: Texas), and the ooc schedule started to get more competitive.
Looking at our schedule and the ooc losses from those years:
2014 - Maybe he beats BYU and UCLA.
2015 - A competent offense may make the Notre Dame game decent, not like Mack had recruited a QB though by this point. Maybe he doesn't choke away Cal
2016 - He probably doesn't lose to Cal
2017 - Maybe he beats Maryland, I doubt he beats USC, I think we were all surprised how close we came to beating them.
2018 - Again he might beat Maryland.
2019 - I don't think he beats LSU.
He might have a few more wins, but the way the offense had looked in his final years and the lack of good recruits coming in and player development, I think it may have gotten worse. Charlie tried to instill discipline and did okay bringing in some talent but there was a lot he did not do well. Herman has brought in some talent and has done somewhat better. Not as many blowout losses as in the last two regimes.