What other threads are there relating to Avernus? Actual unresolved plots that would matter to our character, not just things/people that get mentioned? Zariel doesn't actually matter to the plot, she's just talked about. Gortash is dead so his stuff doesn't matter anymore with the infernal engines, etc. Raphael can just die, much like Karlach, so he can't be the focus of a DLC. And unless we've had evidence to the contrary, I don'tbelieve that Avernus was planned beyond just being a cool idea that they mercifully cut out of the already bloated story.
