The main reason we need item sets so badly is because of how atrociously the items are laid out in the shop, you either have the way too limited recommended items, or you have the check box garbage/every item in the game in order of price. It takes multiple clicks to find a big item! If I decide one game I want Gargoyles Stoneplate on a champ that it is not in the recommended of, I gotta click an item with armor, then chain vest, then gargoyles. Some items build it to so many items to need to scroll right once to get to it. It would be so much easier if we could make an item set with all the completed items that applies to all champions, currently I have something like this, although I seem to have 2 and the game keeps swapping them up on me, but currently they don't work for Xayah, they also don't have Gargoyles or that new shitty MR item, Abyssal and Banshees are in the wrong sections since those items swapped purposes (Although the new Mr item would probably replace Abyssal entirely for me)
I'm on the PBE right now, in order to make sure things are actually functioning how they should and they are not. I can select a single champion for an item set. Please fix this before adding it to live. Idk why the new client has to prioritize aesthetics so harshly over practicality.