Item sets

So did riot ever give a solid reason why they removed them? Saying that not everyone uses them is not a reason at all. People still use them. And in a game with roughly 130 champs and give or take 100 total items, item sets are very important, especially for new players. New players can't remember the names of items and what to build. I have been playing for over a year and I am going to have issues with this. I should be fine with my mains, but beyond that I'm screwed. And maybe I'm totally blind and they said they will be bringing them back or something. I just don't see any benefits of removing it, like what's the up side?