Here are some potential ideas. 1) Give me Sazza as a companion... well more like a subservient underling. I am a True Soul afterall. 2) Give me Minthara as a companion, maybe I can bend her to my allegiance rather than the Absolute's down the road. 3) Give me a Goblin Horn to summon a goblin raiding party to aid me in difficult fights. 4) Give me thralls and minions of true soul. Like the two siblings I meet on the road, they could be interesting characters to learn more about. And who knows maybe to torment or reward as I see fit. 5) Give me the option of not killing the refugees and druids in a massive massacre. Weren't there talk of slave traders in Goblin Fortress? Give me choices! Maybe certain characters can be spared and sold, Why should I kill Mol and her buddies when I can just spare them and have them work for me!
There are a lot of options. Maybe the evil playthrough can impact my camp look as well. It would become more savage looking, maybe I can hire Drow and Ogre merceneries. Have evil pillage and conquest questlines... something! Honestly burning the orphanage just because it makes me so edgy is not that attractive of a choice.
+1, You are totally right; I think this is precisely why they wanted us to play evil. So feedback like this can be given in regards to that content. I feel like you nailed it.