Halsin should be at least level 10 IF they make him a true member of the party, which, storywise, they should. Makes no sense for him to say he'll come with you but he'll just sit at your camp and do nothing. They have to at least come up with a REALLY good reason why he doesn't join you in fights.
So, the issue with him being a party member is he SHOULD be OP compared to the rest of your party, which then throws off balance.
So, good luck, Larian, solving that issue you created for yourself. Storywise, he should be a playable party member, but gameplay wise he should not for sake of balance. I personally would like him to be a playable companion, but only if done right.
