I'd say, morinth is what Asari really are, slut, screws everything that moves, and kills mercilessly, that is Asari, no matter how you look at them, the expanse of their territory and culture turned them to more civil when they found the Citadel, even more so.
Samara is the better choice indeed, at least she takes responsibility for her own actions, Liara used to be different too, it seems Asari are easily corrupt, but I guess stress and power does that to anyone. Personally, i am a very evil natured person, I would gladly kill 85% of mankind, but I would do it gently and quickly, nearly instantly is possible, but I would still do it, and why ? because I believe there are far too many of us for our own good. You can say I am Chaotic Neutral. Reapers don't care what happens with life, they just do what they were programmed with so long ago they probably don't even remember who built them, and I bet someone did. Morith kills whatever, whenever, however, best during sex, you can say Asari are a humanity^3, we are like them, just not as badass.