Here's a quick breakdown because the rankings can be a bit misleading. Last year, there was not THAT much difference between the teams for defensive rating. This is not a wide distribution here.
If we were to improve by about 5 points per 100 possessions, we'd go from being the 29th ranked defense to the 7th ranked defense. And all it would take is... in the entire game, commit one less shooting foul and force one more miss from 3.
For example, NY climbed from being ranked 22nd to 3rd in one summer the year prior, largely with the same roster (+ Thibs and some vets). And it was with allowing 5 fewer points per 100 possessions like I'm hoping we can do. Yet this relatively minor change in the numbers resulted in a massive cultural change among how the league views NY.
It shouldn't be that hard for us to climb into the top 10. A minor dip in the offense should be expected with an increased defensive focus, but being in the top 10 on both ends of the floor is the first step to contention. It should automatically result in 50-55 wins in the regular season.