Hi Manutoo,
I think it's way too easy to guess and return an accel shot deep during rallies. I was watching an online match and so many of the rallies were where one player got a short ball and blasted an accel, the opponent guessed the right direction and could return the ball back deep with ease completely repeatedly resetting the point, regardless that it was a full power accels. If you guess the right direction, it is way too easy to return the ball regardless of the quality of the shot, resulting in a bunch of ping-pong points and excessively long rallies. One player even had to start hitting winners down the middle, cause of how easily the other player could return a full power shot and completely reset the point if they guessed the right direction. The issue stems from the lack of a timing mechanic probably, as if u guess the right direction and end up in a somewhat decent position, all u have to do is hold normal shot to completely reset the point without any difficulty/skill.
Cheers.