Why a bat positioned in horizontal direction naturally has the difficulty in dominating the bounce of the ball?
The reason is simple,the area of certainty of a ball hitting on the bat will be vertically very less compared to the area of certainty of a ball hitting on the bat positioned in straight or vertical direction. When a batsman plays a ball with the bat positioned in horizontal direction, here during the connectivity of a ball with the bat positioned in horizontal direction, here during the connectivity of a ball with the bat, at this particular point the availability of area of certainty of a ball hitting on the bat will be more only in horizontal direction which is absolutely suitable for dominating the deviation of spin or swing of the ball.
Eg: Sweep shots, horizontal square drives, cuts etc…
During the connectivity of a ball with the bat, the vertical area of certainty on a bat positioned in horizontal direction is nothing but the width of the bat which is less, limited and constant through out the length of the bat.
Therefore when we really discuss about the genuine bouncing delivery, the height of the ball after hitting the pitch increases vertically more than a regular normal delivery which indeed could require a more vertical width or in fact more vertical area of certainty on a horizontally directed bat. But unfortunately the vertical width on a horizontally directed bat is naturally less and limited the bouncing ball may hit top edge of the bat or may deceive the bat.
Note: Today modern day batsmen are trying every shot which are not in the cricket book. Some of the shots like upper square cuts, short arm upper cuts are used by the batsmen to dominate even the good length bouncing deliveries. At the end of the day the batsman needs to judge the bounce of the ball since naturally horizontal bat shots are really not a safer option to dominate the bounce every time specially in a test cricket.