I think tennis, baseball, badminton, ping pong, and other similar sports should change the rules. The athletes should be required to use both arms to manipulate the racket, bat, paddle, or other tools. For the first round, the right arm primarily wields the tool. For the second round, the left arm primarily controls the tool.
For example, in baseball, the 1st and 2nd innings should require all athletes to bat right-handed, throw with the right hand, and wear catching gloves on the left hand. In other words, Team A bats right-handed, while Team B throws with the right arm and catches with the left arm for the 1st inning, and then the two teams switch offense and defense roles in the 2nd inning. For the 3rd and 4th innings, all athletes must bat left-handed, throw with the left hand, and wear catching gloves on the right hand.
For the 5th and 6th innings, the offense primarily uses the right arm while the defense primarily uses the left arm. In other words, during the 5th inning, Team A bats right-handed, while Team B throws with the left arm and catches with the right arm. For the 6th inning, Team A throws with the left arm and catches with the right arm, while Team B bats with the right arm.
For the 7th and 8th innings, the offense primarily uses the left arm while the defense primarily uses the right arm. More specifically, during the 7th inning, Team A bats left-handed, while Team B throws with the right arm and catches with the left arm. For the 8th inning, Team A throws with the right hand and catches with the left arm, while Team B bats left-handed.
For the 9th inning, every players gets to use any arm as his/her primary arm.
Forcing these athletes to use both arms requires greater skill and a more balanced workout. It could also decrease the probability and severity of injuries caused by excessively repetitive motions. It may create enough variety to make the sports more fun to play and watch.