Halsin doesn't have the parasite, or so we can assume because he doesn't trigger the mind connect thing that everyone (excluding Gale... ahem... cough... did anyone but me notice that Gale is the only companion who does NOT trigger the parasite mind connect thing?... but I digress...). Therefore, it is not likely that Halsin would be considered a true party member. Karlach, on the other hand, makes sense as she is definitely one who is Afflicted. Does it mean ONLY characters who are Afflicted can be companions? No. But that seems to be the way they are going with the story.
Nevertheless, Karlach doesn't join you yet. I'm hoping that when the game rolls out completely she will join you right away. I like her character and want her as a companion. (She could do with a few less F-bombs if you ask me, but I can live with that.)
As for Halsin, he just doesn't make sense as a companion because he's an Archdruid. I actually was getting the impression that they Talkative Skeleton will be phased out, actually, as your Resurrection Buddy after you leave for Moonrise Towers and that Halsin is supposed to take his place. I got this impression with Patch 5. When you talk to the skeleton at the party, he says something to the effect that his time with you is pretty much at an end. He is no longer needed, or something of that nature. So I'm guessing Halsin is supposed to be the party respawn super healer. Again, however, doesn't really make sense to me. The man should be helping you explore and fight, not just sitting at camp waiting around just in case you die.
I did think of a good way to have Halsin as a playable party member and still stay true to story and D&D lore, etc. Level Drain. If Halsin explained that he got captured because an associate of Minthara's, who returned to Moonrise after the attack on Waukeen's Rest, had used a medallion or magic item of some kind that drains people's levels, permanently, that would do it. Halsin was once a level 15 or something druid. He went with the adventurers to check out the cult at the temple of Selune. They were running. The Drow used the magic item and drained Halsin's levels. Goblins swarmed him. He fought hard, but each round the Drow drained another level until he used up the magic item's 10 uses. Now, Halsin is only level 5. He has significantly lost his power because of the wicked Drow's amulet. They could even call it the Vortex of the Absolute, or something crazy like that. Halsin, therefore, could be explained as being so weak because of evil magic. Now, he feels he is no longer fit to lead the grove because they need someone so much more powerful and capable to help heal them and recover.
There you go. You're welcome, Larian. I solved your "Halsin is too weak mechanically to fit the story." Now you just have to actually have him explain it... or something similar... in the game itself.
