Innervating Locket was removed because champions with very short cooldowns and/or double-activate skills were able to abuse it, essentially becoming a mobile fountain for their team in a fight. The amount of regeneration obtainable from it was absurd. Then you get teams of Gragas, Udyr, and Sona, each of them using a Locket. Good luck killing any 1 of them.
As for "reworking" it, there was a Journal of Justice article about the League artificiers having a catastrophic accident while working on some form of locket, that was intended to be used in future League matches. A few patches later, Locket of the Iron Solari was added to the item shop. This has pretty much been taken for unofficial confirmation of Innervating Locket being replaced with Locket of the Iron Solari.