Hrm....
Maybe they can pull a page out of Kindred and allow the Xin player to "challenge" a target champ, and then pull another page from Garen's Villainy to allow Xin Zhao certain bonuses against said champ and no one else. Gives Xin extra power while making it abundantly clear that he was to jump and destroy THAT guy, no one else which allows the enemy team to play around it. Effect would need to scale with level or ult ranks, as to not be oppressive in lanes.
Would help solidify Xin as a diving champ, and seems like it'd work with his kit. 3 Talon Strike provides window of opportunity to peel Xin before he CC's his target (maybe 3 Talon Strike should work like Morde's current Q instead with ramping damage, and let Morde get something else to help address his own problems), while his ult can be used to make some room for him to take his target down.