League of Legends has a defined way to play it, and the way players actually do. And, while this can be healthy for a game, in some cases, it most definitely isn't.
The previous example of an ADC abusing its AP values was Kai'Sa. Her W ability, which scales with Ap, is a long-range skill shot with a long cooldown.
However, AP items themselves have a tendency to have haste as a secondary effect bypassing this issue. In essence, what we had for a few patches was a long-range Nidalee spear coming at us, and dealing more damage than it has any right to.
There was no sieging an AP Kai'Sa, or fitting the enemy team for control of a neutral objective.
What we have now, may be even worse. Zeri has recently taken to the AP build like a storm, and just like Kai'Sa, is abusing her W ability. however, unlike Kai'Sa, Zeri's W scales with AP and AD alike, both having a good scaling rate, making Zeri useful even if an enemy comes close.
Though, good luck with that, as Zeri has one of the best escapes in the game, with her own brand of a wall jump.
In essence, what we have this time is a slightly weaker Lux ultimate on an 8-second cooldown, with the champion casting it being incredibly hard to pin down and kill. it's almost as bad as the early tank Zeri builds to play against.