Rewards and consequences are integral for (certain types of) evil vs good play. Why would a (non chaotic/sadist) evil person do things that don't reward them? Let alone do things that actively harm them: allying with the goblins offers ~no chance at a cure and only a small likelihood of helping you, given that the cultists you meet have less knowledge about your condition than yourself.
Evil is characterized by selfishness: prioritization of personal rewards over the well-being of others.
Good is characterized by selflessness: prioritization of the well-being of others over personal gain
The lack of rewards/consequences to the evil storyline are significant reasons why it is so lacking rn. Unless, of course, the "evil" route is only for CE characters, in which case sure its consequences are perfectly fine: you get to murder a bunch of druids and tieflings. Also you get Minthara, probably its most enticing reward.
