The tieflings get half killed regardless in Act 2, and the only ones you have any real interaction in Act 3 is Roland and Alfira. That's it. Zevlor is basically nonexistent. The others are one sentence statements zero dialogue choices NPC at Rivington. Act 1 and Act 2 consequences are quickly forgotten and discarded for the jumbled mess of side quests in Act 3. The druids from Act 1 are quickly forgotten about. The Harpers are forgotten about in Act 3.
Honestly, I would have preferred less scattered side quests and focusing on the characters from Act 1 throughout the city and companion quests.
Well its 2 net. You can keep Gale if that is what you are referring to, and Minthara is instead of Halsin. However, the loss of two origin characters is a significant loss of content, on top of all future content with the Tieflings.
This is a huge penalty without any significant upside. It also seems very unnecessary. The game even has a secret tunnel under the druid grove for the Tieflings to escape and its not like this is a completely implausible option given the druids were trying to evict them. If you didn't kill the Tieflings, it would feel more plausible that Karlach and Wyll would remain.
Except it would make no difference because you find in Act 2 that half the tieflings get caught, tortured, and killed by Absolute cultists and the Drider in Act 2, and Zevlor is spirited away. So you know, Minthara, the cultist you helped along the goblins, that same faction you teamed up with kills the tieflings even if they managed to escape the Grove. So it absolutely makes sense that good aligned characters leave your party when you team up with a ruthless, evil drow paladin who sees people only as tools to be wielded for power. Karlach was literally sold to hell for power by Gortash, and Wyll has been a slave to power. I don't know how you expect them to turn on their morals just so you can be evil and ruthless and still have access to their story. It's almost like people don't want negative consequences for choosing evil. Your reward is you get to see the game from the villain's perspective and get the most unique follower race and best class follower, a drow paladin whereas good playthroughs don't have a single drow character and it's all humans and vanilla elves with the exception of Karlach. You also get Halsin as a druid, but druid is a trash class so you will probably respec him to something else. Good players also get another trash class in Jaheira as another mediocre druid, and then Minsc as a trash 2H ranger with no good supporting stat block to play him efficiently unless you respec him to rogue or barb/fighter, and by the time you get to recruit Minsc the game is basically next to over, so he's a wasted character.
