Very good game. Make Rainbow Dash's best attack a Sonic Rainboom which takes up 100 AP.
Also add these stats:
Fluttershy: Level 1
Rarity: Level 3
Pinkie Pie: Level 8
Twilight Sparkle: Level 12
Princess Cadance: Level 20(Boss)
Princess Luna: Level 30(Boss)
Princess Celestia: Level 40(Boss)
Night Mare Moon: Level 50(Boss)
Queen Chrysalis: Level 75(Boss)
King Sombra: Level 100(ULTIMATE BOSS)
And perhaps be able to choose who you want to have after you beat the game once. You can choose after that to keep going with RD or restart it with a new character. You can also do Sandbox mode where you get same EXP as normal but you choose what level each character is you fight. Has to be atleast half their usual level though and no limit to how high their level is.