1- Grips are usually black and not white (the majority of tennis players use white grips)
2- White uniforms for each player for grass court (not official Wimbledon)
3- Huge celebrations when winning a tournament or important match ( get down on the floor or point to the team…)
4- Say sorry to the opponent on a lucky point
5- Drink water or use towel during the break
6- Shout when getting angry after making a mistake
7- changing weather conditions
8- option to call supervisor or medical time out
My suggestion is to show the speed of the serve most tournaments dont have a speed clock so be a nice addition to show the speed of your serve beside your players name and scorecard. There should be a power gauge added to the timing of the ball toss so I can control how much power Im putting on the serve I dont want just to 2 set speeds of serve with just the aggressive and safe speed. Real life tennis players are serving all different kinds of speeds. Gives much more varation to the speeds of serve. Let me choose where to place the ball in the service box by having a tennis ball marker you can move inside the service box before doing the ball toss. if I time the ball toss perfectly have it place the ball exactly where I want it like it is was in Ao tennis 2 I could place the ball anywhere in the service box before I was making a serve. Let me have the choice of serving down the t or out wide.
Also another suggestion is to have a stamina gauge. For 5 set matches would be a key factor in a match. If you have depleted energy levels have it impact on your chances of making a successful shot or serve. have the player run slower once the energy is low. Adding Injuries would add a sense of realism to the game if you have a player with low energy levels and your trying to run at maxium speed have it increase the chance of an injury and give u the decision to continue playing with an injury in the game.
My final suggestion to add to the game would be a momentum bar that fills up when winning points consectively or winning big points or ralleys. A moment bar that also shows a pressure meter if the momentum is against you and your serving with the other player with a break point at love to 40. Have that impact on your pressure especially in tiebreaker or fifth set would add a sense of importance to the points your playing. If you have a low pressure meter have it increase the chance of a double fault or hitting the ball out. Bring back hawk eye challenges would be the finishing touch to the game.