He's not currently a great shooter, but in addition to the defensive skills, energy, and dirt-dogness, he's also a very good penetrator and passer, much better than Jaylen Brown. If he improves his stroke as much as Brown did in year one, he could be a superstar.
The concept of Josh Jackson and Jaylen Brown playing next to each other for a decade will scare a lot of teams if those two reach most of their full potential. They will both be two-way monsters.
I still want Fultz, because scoring was, is, and always will be the ultimate premium in the NBA, but Jackson has DPOY upside on defense and All-NBA upside on offense.