I expect him to be a different type of player, not possible to be the same, neither physically or mentally, similar to Stern.
My guess, barring any further damage(please God). More improvements in ball control, vision and passing. Reduction in spontaniety, increase in recovery time, reduced explosiveness and ability to chase every ball.
Overall a better player, with reduced agressiveness.
The raw talent that every coach previously observed, would be improved, but note it's that raw talent that made him as dangerous as he was. Let's see what the new KJ brings. Good Luck KJ. Learn this new you, dont be frustrated by this new you, master it and yuhself. Dwight and Stern did, talk to them.