Honestly I would have agreed with you but I played healer for the first time in like 8 years.
Ball is sure someone who you need to focus down on and fast.
It is just impossible to heal and deal with him. Usually what happens is, if the ball is not controlled. The DPS jump on the Dive comp. Now you have Ball, Tracer & Genji to deal with.
So yea, counter watch is a must sometimes if everyone needs to have fun and play the game.