Hello,
I'm sorry you don't enjoy TE4.
Let me try to help you.
1) If the AI is too hard for you, just lower its difficulty level. At what difficulty are you currently playing ?
2) If you make too many errors, it means you're not correctly positioned on the ball ; if you have disabled the Danger Zone, turn it back on as it's very helpful to learn how to position yourself.
Alternatively or additionally, you can change your player controls from Simulation to Arcade.
However, if you don't prepare your strikes early enough, they'll always have a chance to end in the net.
How long have you been played TE4 so far ?
3) If you ever play a doubles match again, and your opponent doesn't react to a ball going to him, please send me a Bug Report right away, I'll fix that. (HowTo =>
topic5-31732.php )
4) With 100% in all skills, at Pro-10 level : the max slice speed is around 113km/h with the Slice talent, and 103km/h without the slice talent ; decent accelerations start at 125km/h and can go up to 180km/h.
However, it's true that some slices are just too good, so I'll likely tune these a bit down in the future.
5) Overall, as you might have noticed, the game is still in construction, so things will change from user feedback, like yours..!