Second, I believe that Callandor itself is not flawed as Cadsuane reveals. I'm not saying she's wrong. She states that Callandor was created without the buffer that angreal/sa'angreal are usually built with. I believe this was the reason that the taint fluxes when Rand tries to use it. The only safe way to use it, she claims, is in a circle. However, I posit that the lack of buffer will allow Ralayndha to reach a higher channeling potential than perhaps even the Choedan Kal allowed. The circle would be using the natural attracting/repelling nature of Saidin and Saidar to keep the One Power in check and prevent burning out while Callandor acts as a pure magnifier.