Just a couple of thoughts on Morrigan
-There's no reason for Morrigan to assume that neither Alistar or the Warden did not know a Grey Warden must die in order to slay the Arch Demon. Yes, she clearly with held her plans, but I don't see that as any different than Leliana hiding her past. Just like some people wouldn't want Morrigan around if that was her plan, some people may not want to collect assassins. At least Zevran was a known assassin, but Leliana lied just as much as Morrigan.
-If you believe Morrigan is evil, then clearly, you didn't do her story arc. She's selfish, unsociable and has a very cynical view of the world (all of which she admits), but none of these make you evil. Despite her being anti-chantry, when you threaten the priestest in order to free Sten, she clearly disapproves. There are also a few other senseless cruelty acts that show, that evil is an incorrect attempt to simplify Morrigan.
-And if you actually see the romance through, you see that she is capable of love and isn't the monster that many players make her out to be.