If I understood the original poster concern was that his coach was asking him and other players to "exclusively" go opposite field.
Actually to be honest, I really don't care what stance a player uses. I post information that I found either in books or as part of what I learned when I was a player. The individual player must find what works for him...period.
Lau says in his book that the proper way to hit opposite exclusively is "closed stance" but I made no reference to Lau's preference...which is parallel. Lau admits if going opposite is what you're trying to do the closed stance works best.
Lau says, "Proponents of the closed stance say that it puts the batter in position to hit the ball to the opposite field, as when a right-hander hits it to right field or a left-hander hits it to left field.
And that's true too."If your intent is to go to right field and you are using a closed stance...in what direction should you step if you're trying to go opposite. Your line of step is in the direction where you want the ball to go.
What's seems to be at question here is the extent of what we are talking about. these are subtle nuanced techniques. slight cheating small movements to gain an edge.
Your softball comment is very telling in that no one in BB would ever use that sort of overt action...in BB adjustments to the ball are part of the 6th tool Bob Williams of Areacode talks about.
If you can't make adjustments that make common sense then you lack 6th tool skills.
As you go up in levels your player will learn a lot more by talking with his fellow players, especially the veterans, than he will only listening to the coaches. Coaches have a very narrow view of what they want. The player is the one that has to deliver. Getting the job done is the result they are looking for...don't forget that. I played a long time, but noone will tell you this stuff.
I've spent countless hours teaching my son the subtle aspects of the game, stuff you learn only playing at highest levels.
MaxE