I was considering the possibility that Egwene, if she is Latra Posae Decume Reborn, might be the one to be in a group that would wield Callandor against the remaining Forsaken. Latra earned the title Shadar Nor/Cutter of Shadow, and combine that with the subtly altered way Arthurian legends have been used by RJ, it seems to imply that Callandor might be collectively wielded by Egwene, Narishma and Logain, with some form of sharing of leadership (perhaps with Narishma leading while Egwene and Logain supported him - a position that both could learn from, though Egwene might be able to do this more readily than the latter). Especially the legend the prophecy:

"Into the heart he thrusts his sword, into the heart, to hold their hearts. Who draws it out shall follow after. What hand can grasp that fearful blade?"

I've said Narishma has a greater significance to the story that we won't see come to fruition until after Tarmon Gaidon, but I'm starting to think he will come to his significance during it. The prophecy seems to indicate that Callandor has been passed on from Rand to another, and Rand & Co are so focused on the Power as a solution that they are concentrating too hard on a sa'angreal. Just a possibility.