I also wonder though, the Tiger brain trust puts the equation as "don't swing at pitches out of the strike zone", but how many hitters are trying to do that? How much good does it do to coach players to do something they are not capable of doing? Isn't the real question pitch recognition? It seems if you can give a player some kind of tools to help him recognize when a pitch is going to be out of the zone, then you are giving him something he can use that helps him stop swinging out of the zone, but to just tell him to 'be disciplined" and not to swing out of the zone? What does it do for him if the player doens't know how (or in then end doesn't have the capacity) to get there? Besides make him a tentaive hitter anyway. I can believe there are a few guys who just have to focus better but I doubt that is the case for most.
if you do something like help a guy develop a swing that gets him to the ball quicker so he can wait longer on his swing decision, then you might get better K zone control as the secondary benefit.
When I look at Javy, I see a guy with a long, huge swing who commits before he knows the pitch is a slider. No amount of 'discipline' fixes that without a mechanics change. If I'm coaching Javy, I'd almost rather just work on helping him go ahead and hit the bad pitches he's going to swing at.