As Moghedien said, 29 others had been given access to True Power. I'm assuming that she meant 29 besides her self. Taking out the Forsaken that we know, that leaves 17 people that we do not know that could be Moridin. The reason that I do not like to believe that Moridin is a recycled Forsaken (ie Ishy) is that it just doesn't fit. Aran'gar and Osan'gar were brought back at the same time and named according to their usefulness. If we go by the Aginor/Balthamel theory as to who these daggers were before, they were the first to die and brought back at a much later date after several other Forsaken had already died. If the DO was in the mood to start bringing people back from the dead, wouldn't he bring back all of them at the same time? I think so. Also, when I think about it, wasn't Shaidar Haran in the room when Aran'gar and Osan'gar were brought back? I would find this a much more logical choice. I would tend to think that Moridin is either someone else from the AoL or some modern Randlander that worked his butt off to impress the DO.