Items sets are needed and my opinion on them.
I feel items sets are vital to teaching players what they generally want to build,I actually set up a few for my brother so he knows what to build, having these item sets also help people with new champs as they know what to generally build. I have no idea why Riot is deciding to remove them, as it really limits to memory or alt-tabbing out to check google for what to build next on that adc you've been trying to play. ( My brother is MEH at the game and plays Sion and Malphite, if he doesn't know what to build he'll start building AP and then it goes down hill. )