I didn't even kill Anders and I severely dislike that terrorist. No matter what bad thing a character has done, I'll always try to redeem because I'm too nice idk? (except Vaughn in Howe's dungeon? He dead.)
So even major characters that have or had serious flaws/commited crimes like Loghain, Anders, Blackwall, the Egg, Cullen etc I would have a hard time leaving in the Fade.
Except Stroud, which I chose to leave behind without even thinking. We should all take a moment to remember the true hero, Stroud, who had to die because there wasn't a third Warden option enough people even remembered.
To answer the original question of this topic before someone gets their feelings hurt because someone said they didn't like their favourite character:
I'd leave behind my two Wardens, even my Prince-consort Cousland because Purple Hawke.