I haven't really thought any of these through, so they might be terrible...but here's a few.
1. Push the 3 point line back 1.5 feet. If that means widening the floor by 3-5 feet, then fine. If you don't want to widen the court, then have the 3 point line a uniform distance, thus eliminating the corner 3. This should slightly reduce overall 3 point percentages and create more space to operate and guard in the mid-range.
2. Shrink the width of the lane from 16 feet to 12 feet to match the NCAA. Change offensive 3 seconds to 5 seconds. Hypothetically, this should put a little more emphasis on big guys and improve/encourage post play.
3. Stop rewarding offensive players for creating contact. If you create the contact in any unnatural way, then no foul. Give the defense more leeway to contest shots. Hopefully, this would encourage players to pull up from the mid-range, shoot floaters, or pass more often rather than just flailing wildly in hopes of getting two free throws.
4. Start calling traveling, moving screens, offensive push-offs, and egregious carries. I don't think you can totally fix the carrying problem, because it's so ingrained at every level of basketball. But don't let the offensive player use it to gain an impossible advantage. With regards to screens, calling moving screens--primarily on-ball--would reduce the effectiveness of the pick and roll/pop and incentivize teams to run/initiate alternative offenses. The value of enforcing traveling violations is obvious.
5. Require players to appear in 73 games to be eligible for any awards and thus contract incentives tied to those awards. Asking players to show up to work 90% of the time is not unreasonable. If it truly is unreasonable, then the length of the season needs to be shortened. With that said, in 19 seasons John Stockton played 82 games 16 times in a much more physical league than now with many deep playoff runs.
6. Reduce the number of playoff teams back to 16. Put more emphasis on the regular season.
7. In the first round of the playoffs, reward the higher seed with an automatic win in a best of 5 series. For instance, in the 1 vs. 8 matchup, the 1 seed would start the series with a 1-0 lead. Therefore, they would only need to win 2 out of 4 actual games to win the series. For the 8 seed to win the series, they would have to win 3 out of 4 games. This puts a huge emphasis on the regular season and getting a top 4 seed in your conference. Along with this, I would potentially consider eliminating the conferences all together and just seed the teams 1 through 16, and giving the aforementioned advantage to the top 8 seeds.
8. Give all lottery teams an equal chance at all picks. Thus the 14th worst team would have the same chance at the first pick as the worst team and vice versa. The goal of this would be to discourage out-right tanking.