I feel like Larian should of added a Paladin to complement her but then again Paladins also have magic.
Karlach is going to join your camp as a paladin (if they still keep her as her current class)
In my opinion, the game doesn't have to be 100% DnD just based on it is fine. DnD is based on existing lore, they just tweak it for their own. So, Larian can also do the same for a video game.
pretty sure a lot of people who are hardcore DND tabletop players would strongly disagree on this.