Killing all the High Elves of Dalaran might settle everything once and for all, but it would have no symbolic significance. Having Aethas and the others serve their country again was impossible, too. What they had done was treason. Giving them posts would amount to buying their submission with amnesty, something no capable government would do.
In Azeroth, Patrick would not do it either. If he gave Aethas a post, the consequences would be tremendous. It would practically be telling every elf: go ahead and cause trouble, go ahead and betray us. As long as you are strong enough and have enough people, the Council will not dare do anything to you and will even promote you.
If the Silvermoon Council did that, it would have plenty to keep it busy in the future. "Want an official post? Murder and burn, then accept amnesty." Patrick would never allow such a thing to happen. If even treason could be forgiven, what would the other High Elves think? What would those honest, law-abiding elves think?
"How should we establish a standard for judgment?" Lady Luminas Sunstrider, seated on the outskirts, radiated cold all over, and even the seats beside her had developed a thin layer of frost. "Or rather, which elf will preside over this trial?"
"Investigate these people one by one and assess them individually. For the ringleaders whose offenses were grave and whose actions seriously harmed the Kingdom's interests, set a date and execute them. Even their remaining Soul Shards will be handed to the Dark Curse Burning Legion to feed to the Naaru. That will give the Naaru some energy and strengthen the Dark Curse Burning Legion and the Dawn's Edge Burning Legion, letting them make some contribution to the Kingdom. Those guilty of major offenses will be dealt