Love the "historic turnaround" rhetoric. People are fixated on rank, rather than amount of improvement needed. There is less variance in defensive efficiency than in offensive each year; last year there was only 70% as much. That means that for a given amount of improvement in points given up, there is a greater improvement in defensive rank than you would see in offensive rank with the same improvement in points scored. This past year IU scored 10.2 more points per 100 possessions against the average D1 opponent (Pomeroy's adjusted offensive efficiency) than they did the year before. If they were to improve to the same degree in points allowed in the upcoming year, their adjusted defensive efficiency would rank them as the 31st-best defense in the country (using last year's defensive numbers for the other teams). That's giving up about 6.6 fewer points in the average game than last year. While that may not be easily done, it's definitely doable, and definitely not "historic".