@Riot Xypherous, Can We Talk About Locket?
This post is only one of many in this thread that Xypherous makes, so I suggest everyone read the Rioter Rundown.
Anyway, the main takeaway is that Locket of the Iron Solari actually influences the amount of AP and damage champions can have, and thus if it is not in a game champions have way more magic damage than Riot is intending them to have. Thus, Xypherous has pretty much admitted that if you're not rushing Locket, the enemy team is just going to have a stronger mid game than they should.
He also mentions later down that Riot will likely have to remove Locket from the game at some point and rebalance AP and damage across the board. I think this is all important information to have so I would like if the general boards and its players could weigh in, not just the PBE players. Leave your comments for Xypherous and hopefully he'll answer any questions or comments you guys have.