Loghain must die. I find it implausible that he would not undermine the authority of the next king/queen and allow them to rule in a way contrary to his desires, even if he's officially stripped of all power. These things never go well in real history, he's basically guaranteed to show up with an army at some point to take power.

And his big treason move is one thing, but sending assassins after me, putting a bounty on my head, and doing everything in his power to see that I don't survive? No, sorry, unacceptable. My "real" DA playthrough was 100% a Korean movie vengeance quest.