I just finished the cleansing ritual of Orr, so maybe I haven't seen everything yet, but he doesn't seem too bad to me. I've heard that people think he's a Gary Stu, and while I would say he's dry in terms of character, he doesn't seem like a Gary Stu. The dialogue never gave me the impression he was the greatest necromancer in Tyria or anything like that, rather he was just competent. To me, he's like a tradesman with several years of work experience under his belt. He's probably rather special in the eyes of the Pale Tree, but nothing too extreme. His Wyld Hunt consisted of him cleansing Orr, but that's it.
He'll probably join the forces in taking down the dragon, but he's certainly not doing it alone. As such, I never got any kind of, "chosen one" vibe from him. If anything, the player character is closer to that niche. The only negatives I can think of is his marshal status and his lack of character development. He never goes through any kind of struggle, and he picks up his role as marshal with ease despite never leading such a large force before. As far as I remember, he's never made any mistakes, which is unbelievable. Overall, I do think he's a rather dry and boring character, but I don't hate him. Does he do something later to earn that ire?