1. Running backwards is indeed slower than running forwards. That's a limitation of the human body. Except if you watch real tennis, the players simply turn 180 degrees and run in that direction, then reposition themselves when behind the ball. It could be pressure/time sensitive, so if you hold for 2 seconds you go walk backwards and if you hold it for 4 you can run forwards moving back.
Alternatively, you could make the input very specific so you know that you weren't just trying to walk backwards, like a half circle [on controller or left and right simultaneously and then back on pc] so your player knows that it's time to turn around and run (there's no utility in facing away from the net and NOT running) instead of taking it slowly. I'm not saying this should be done without penalty. Maybe you burn twice as much stamina if you have to turn in place and run full force in the opposite direction. Maybe just the turn burns a significant amount of stamina so you can't spam it, although, and this is rare, some players CAN cover all parts of the court, even if they're running on fumes.
It would make the rallies make more sense, bc the only thing missing from this game is a satisfying/dynamic net game. It doesn't make sense that everyone to a man is dead meat as soon as they are at the net if someone lobs over their heads, outside of the top 100.
I was thinking that no tennis game would ever get close to the artistry of playful net play, but that one change could alter the entire game and bring that fantasy to reality. I suppose extended animations could be between the legs shots a la Monfils/Alcaraz, over the shoulder shots at different angles, flick shots over the same shoulder, no look drop shots, etc., but those specific suggestions are just icing on the cake that don't necessarily need to be added by the one man developer.
That one change, however, could change the entire game, with modders picking up the slack for those flashier animations/trick shots.
2. Why is there no stat that specifically targets hitting accurately while running? Certainly some players are very good at hitting accurately on the run. I know Net Presence says it does address the nerf penalty to moving shots, but I'm assuming it effects closing the distance to the/at the net, not running full speed to track a ball out of reach.
3.Why is there no animation for, when you have enough time, cooking the shot while [simultaneously] stepping around the incoming ball to get access to the entire court [specifically with a forehand groundstroke]? It seems like a missed opportunity, bc this is something pros do constantly. It also puts the opponent into the difficult position of having to guess where the shot will go, bc it's going there in a hurry.