I came into this thread because I too have this issue and a few seasons ago I was out nearly every week LBW playing around my front pad. The only thing I found that helped was to introduce a small trigger movement that saw my back foot point down the ground, which, I think through making me momentarily imbalanced, meant my front foot had to move to find a more natural position. It's certainly helped me play straighter better.
However, reading the whole thread has now seen me looking up baseball coaching techniques, and from what I can see (and what I already thought) isn't weight transfer fundamental to a baseball swing? Don't most batters transfer weight back in a load up phase before an explosive movement fires the weight forward? That weight might not move forward of the front leg, but it has to go somewhere, no?