The assassin rework has had a very unusual and unexpected side effect:

Pretty much every assassin counters now, and most of them hard counter her.

Now I can hear what you're thinking "Assassins hard countering Kayle? Kayle shits on assassins!" Hear me out on this one. In the past, Kayle would beat assassins by harassing them in lane, pushing the wave constantly, and carefully timing her ult so that if they try to all in her, she can prevent most of their burst, and then beating them with her superior DPS once they've committed to the fight. But with the assassin rework, Riot lengthened assassins burst patterns in exchange for higher overall damage and greater utility. For most squishies, this is a worthwhile tradeoff, killing the adc instantly is the biggest strength assassins had against adcs in teamfights, losing this ability unless very fed is a huge overall blow to those champions assassination potential.

But for Kayle, this increased assassins effectiveness against her to an absurd degree. Lengthening their burst windows means that Kayle can't simply block all their burst during the duration of her ulti. Giving them greater utility gives them far more options to outplay Kayle compared to before. I've played Kayle against multiple times since the rework and all 3 matchups went from easy to basically unwinnable overnight. , who already did fairly well against Kayle, is now also unwinnable beyond lvl 6 since pink wards can't reveal her in stealth anymore. were both reworked in ways to give them much more sustained damage, to the point where they can simply wait out Kayle's ult and then kill her anyway. The only assassins that aren't largely unbeatable 1v1 are , and even they have the tools to simply outplay Kayle and kill her even if she manages to block their entire ult damage.