Here are some pretty tested all-star sliders I came up with:
User Pitch Meter Difficulty: -40
Pitch Speed: -15
CPU Pitcher Ball Rate: 12
User Pitcher Fatigue: 12
CPU Pitcher Fatigue: -7
User Pitch Control: -25
CPU Pitch Control: -40
Bullpen Fatigue Rate: 0
Bullpen Fatigue Grace: 0
User Batting Contact: 5
CPU Batting Contact: 0
User Batting Power: 10
CPU Batting Power: -10
User Bunting Ability: 0
CPU Bunting Ability: 0
User Foul Ball Frequency: 50
CPU Foul Ball Frequency: 50
CPU Swing Frequency: -25
User OF Speed (Manual): +2
User OF Speed (MVP): +2
CPU OF Speed: +2
User IF Speed (Manual): 0
User IF Speed (MVP): 0
CPU IF Speed: 0
User Throw Speed: 0
CPU Throw Speed: 0
User Throw Accuracy: 0
CPU Throw Accuracy: 0
User Catch Errors: 25
CPU Catch Errors: 40
User Dive Difficulty: 0
CPU Catch Effort: -7
User Baserunning Speed: 0
CPU Baserunning Speed: 0
User Runner Aggression: 0
CPU Runner Aggression: 0
User Runner Steal Speed: 2
CPU Runner Steal Speed: 2
User Runner Steal Delay: -3
CPU Runner Steal Delay: -3
CPU Steal Rate: 7
Runner Injury Frequency: 0
Pitcher Injury Frequency: 0
Batter Injury Frequency: 0
Fielder Injury Frequency: 0
Pitching MG Difficulty: 5
Try these and leave some feedback, good or bad, so I can adjust to what you guys think.