I don't think Halsin being playable in Act 1 will ever be a thing. Since Minthara is his antithetical counterpart in Act 1 and she's forced to Moonrise Towers (whether you spare her for good playthroughs or side with the goblins) it would be unfair to have him playable way before her.
I do find him forced into your camp unreasonable and if they had to pander to the Halsin simp crowd (since Swen really has a soft spot and favoritism for a non-origin companion for them) then they have to be fair with Minthara as well.
Not to derail your post, but I'd much much rather see polish in other aspects of the game and just have someone mod your request.
