Not 100% sure what the problem is with consistency. It's easy to think you can make a mental adjustment but when you've played all of the those years of youth baseball, travel ball, and school ball just hammering weak pitching, your muscle memory gets pretty engrained with bad habits. You see the same thing with the young pitchers who can't seem to have command from the stretch because they never had anyone on base growing up until they hit college. Some overcome, some don't.
I just hope this is truly a new approach and not just some brief respite after hearing about Kingston's love of launch angles and how games are won with crooked innings (i.e., homers). As a lifelong Yankees fan, I've seen Boone use this approach to get the Yankees only as far as a team with good pitching. However, even the Yanks appear to be moving away from the approach.