Locket should have a sister item that gives armor aura instead of MR

I feel like half of my support games I end up not needing any MR because we are playing an all AD team and I want a lot of the stats that Locket gives but don't need the MR. I thought it would be beneficial for supports if they instead had an item that was nearly identical that gave an armor aura instead. This would also be beneficial in lane where you don't really need MR most of the time unless you have an oppressive Brand down there.