I agree with a lot of criticisms (not all) that you make. But Demandred's transformation from the guy who doesn't want to get his hands dirty, and is the cold, methodical general, to a man seeking to regain his honor in some perverse manner, and hopes to lead under the DO so that the changed world would have some people he likes survive and thrive is something that RJ left notes for. Brandon and Harriet made the choice to cut that entire arc out of aMoL to preserve the srurprise of Demandred's arrival in Egwene's battlefield.

While that was a bad decision, IMO, at least we won't loose all that development. Its all coming in a "short story", which is a collection of Demandred PoVs. Brandon has also said that the resolution of some issues, like the Eye of the World, will be found there. So wait for that before you pass final judgment on Demandred's arc. You've only seen the end of it.