Wasn't "Sphene" we met just a memory that misunderstood her original directive (or took it in a direction that was likely never intended)?

She was an invading ruler with an intent to either conquer or kill the people of Etheirys - it was never going to be a peaceful resolution. We handled that quite well, I think.

Not only that but it's not like we forced her people to stop consuming souls, either... they still do that. We didn't change their way of dying and living.
It's still brought up in quests that our WoL is making a personal choice to not use the soulconsuming tech.