Well, none of that sounds like a good and healthy reason to me.
Far as I can see, there is one good reason to have a champion be Hybrid: flexibility in their build paths. (But if you have other reasons to add to the list, I'm still open.)
Problem is, if you want to preserve this flexibility in build paths for hybrid Champions, you need to get rid of hybrid Items. If Hybrid Items are any good, then Hybrid Champs aren't flexible anymore, they are forced into buying the couple items that are specifically tailored to them, and it's even worse, you have even less flexibility than being only AP or only AD.
So no, we shouldn't rework hybrid items. Like, at all.
And when you look closely at it, the few Hybrid Items we have aren't Items tailored to Hybrid champs, no, they're just Hybrid to make them purposely gold-inefficient for the majority of the roster, in order to ensure we can control who get access to their super powerful/game-warping Passives.
A quick word on Eve's specific case, even if I'm no expert. The problem with Eve being Hybrid is that giving flexibility to Assassins most often means giving Assassins the possibility to play Bruisers without counter-play. See "Tank" Akali, Ekko, Fizz, etc. And we use to call them "Tank", but the word isn't right, they are durable but they make horrible Tanks, they are more like heavy hitting Divers or more mobile Juggernauts.
Jumping back to the "it's hard to itemize against Hybrid champs": Not really. Because Hybrid champs also have more difficulty itemizing for Penetration, so squishies are still more afraid of a pure AD or pure AP Assassin/Burst mage. And Tanks/Frontliners will just buy one MR+HP item and one Armor+HP item and will laugh at you.