Demandred is a great general, dedicated by his skill and experience to marshalling an extremally important military force, of scale and value as huge, as a trollock army in the Blight. Shara is one posible place to utilise his merits, but this land seems to be located too far away from the main theatre of the Last Battle. Logistic problems connected with transportation by sea and concenration in a given spot of, say, 500k troops with supplies and civillian services would be enormous. Marching troops through Aiel Waste will cause imminent disaster. IMO, Demandred was given by Nae'Bliss equally important post of the CIC of the Seanchan EVA and currently is posing as a general Galgan. Semirhage was behind all political maneuvers, he was purely involved in military tasks. He supported downfall of Suroth, millitary incompetent and nusance, creature of Semi, not his. Nobody can blame him for unproductive sending of 150k soldiers to AD, because it was triggered by Greandal and ordered by Suroth herself. Galgan's behavior as a professional soldier, as we know from KoD, fits precisely character of Demandred. I expect from him to mantain high profile of a military man, during whole course of thorough torture appllied to him by Seeker Morr, as, I presume, will happen in ToM.