Locket is still an amazing item and I get it on almost every support
I've noticed a lot of people not getting it after the nerfs to the aura.
The active gives every member of your team a 200-300 health shield, it's like a rank 5 Janna shield on every single member of your team. Usually at least 2-3 members lose the shield by the time it goes down, resulting in essentially 600 health shielded. The health and magic resist alone make it almost as good as a banshee's veil, add on a shield and an aura and it's a must have unless the enemy team is 5 ad.