I think all of the characters will have multiple ways they can end up depending on the path you take in their individual quest lines. I also disagree that the game considers it "evil" for you to turn Astarion into the monster hunter. The companions have their thoughts about it, but consider that the tadpole is affecting them as well. They're all sharing a psychic connection and the presence of the tadpole may be bonding them in some way, motivating them to stick together and protect each other in ways they don't understand. That would explain the party disapproval from handing over one of their own. Many people are having very different experiences with the characters and your experiences with them seem much different than mine. The game is still in EA and from what I can tell, many scenes are being worked on and updated each patch. Final release may have the RP you're looking for. Just have fun and play the game in a way that makes you happy.