I agree that the way they ultimately implemented Halsin was just terrible overall, but I do wonder if maybe Halsin fans were expecting too much from a character who was only ever meant to be a supporting character? I feel like I see this happening a lot not just with Halsin but with all sorts of side characters; people build up these grand ideas of how great they would be if they were part of the main party and want them added to the party and I just think... those characters aren't written to be part of the main cast. They're not going to have anywhere near the kind of quality content you want and you'd probably just be disappointed if they were added. The same thing seems to have happened to Minthara.