ITT: We think of new abilities or moves that would return former champion pokemon to their former glory. Bonus points if it simulates what made it awesome in the first place.

Persian used to be a fast crit machine. Here's an ability that would make into that again.
Predatory Instinct- If this pokemon moves first, it automatically becomes a critical hit.
There, probably broken, but Persian's stats are sort of crappy, so it might be OU (or at least BL) if it had this.