I wouldn't characterize it as bad writing as much as sort of predictable. That said, there is nothing wrong with somewhat predictable aspects of a character's backstory or behavior. Telegraphing some of the characters motives and such to an extent is necessary, and writers do have to be mindful of finding that middle ground of meeting people who are bad at reading people and folks who do not know much of the faerun lore to begin with. Characters in the old BlackIsle games weren't exactly deep either, and while I don't think we need to hold those as the standard, it is worth keeping in mind perspective wise.
