I think the OP makes a good point -- I would support some sort of warning and an option to remove Astarian from the game. I had no desire to have the vampire from SoD/BG2EE in my game, period, and there was a (very hard to find) way to ensure that character never showed up.
I haven't had the experiences that the OP has and so I react differently. I want Astarian in my party but I also want to give players options and warnings.
I read the boar as exactly that; he's shifty, and if you pass dice rolls you work out it's been drained of it's blood by two puncture wounds in the next. Pair that with the fact this elf obviously doesn't look like a normal elf, and I saw the midnight snack scene coming like a train with it's horn blaring. If it's not hard coded to be before the midnight snack, it should be to clue players in. It can be tweaked, so he approaches and asks, but that both loses the drama of the scene and (from what I've seen of him in action) undermines Astarian's character.
To say
nothing of the character splash on the sight, the live demo earlier this year where sven played as him and the origin option players will be able to click on and read about him.
I'm regret it upsets you and OP, however I'm not sorry this scene plays how it does. The game is rated mature, there are clues to his nature, and as others have said, you can immediately punish him for his attempt. The next time you start the game from the beginning you can 'forget' to recruit him too.
