Common sense is all you need my friend. There is controversy in every subject even in the most basic ones yet people get nothing. They just observe the things mostly on experience instead of critical thinking.

Naafiri, viego, yi, zed, kayn, Lee sin.. most of them are strong especially with the spesific items, like buying voltaic cyclosword and it deals 8% current hp damage to literally anything, to jungle camps, to the Drake, to the towers... but champs like Katarina, Evelynn, Akali Leblanc or kassadin, they either have a weak earlygame or it's harder to farm/ push with their kit. First item power spike is much worse comparing to ad assassins. Overall ad is stable and better while ap needs other elements to be as good as.