I am underwhelmed by Halsin as a personality.
He's just a big dumb boy scout. Despite being hundreds of years old and having been in charge of the Grove for a number of them, he is content to sit around in your camp or trail after you like a puppy.
He is chill without being engaging like Karlach. He has a leadership history and age advantage without being a wise advisor like Jahiera. There's nothing of substance to him beyond being a f-boi.