Yep we might've just been talking past one another on certain parts of this. There are a lot of guys that add 8-12 but its very difficult to do, and like you also had said, there's genetics and other factors (will he have to deal with an injury or something that prevents this type of dedicated/focused training, etc etc).
If he *does* add significant amount of bounce, it shoots him up several notches as a player, because its something that positively affects nearly every facet of the game of basketball. Four years or so from now we could see Keaton as a top 10 player in the NBA with his size, length (6-11 wingspan), skill and shooting ability.