"Moridin was gathering the Great Lord’s forces for the Last Battle, and his war preparations left him very little time for the south —though south—though his two minions, Cyndane and Moghedien, occasionally showed their faces there.They spent their time rallying the Darkfriends and occasionally trying follow Moridin’s orders that the two ta’veren—Perrin Aybara and Matrim Cauthon—be killed."

From this quote, it shows that Moridin spends very little time in the south. So, unless Graendal is mistaken about what Moridin is doing, it seems very unlikely that Moridin is Taim. Had to throw this out there for all you Taimidin believers.