Why No Personal Item Build Creation in New Client

So I was talking to a friend that just started and he likes to play Yi but i dont know my build off hand for him so i couldnt tell him what to do, so i was going to go under my item sets in the new client only to find we cant do it anymore, I am kinda mad because i used it for every champ i played and now when i want to learn a new champ and have my own custom item set ready so i dont have to waste time scrolling through the item shop looking for an item i cant thing the name of. I have to no go online mid game to see what the item build is that i want and waste precious time i could be using to help my team against my opponents. We need this feature back and i dont understand why they would ever take it out.