Interesting stats in the statistical analysis: "The most decisive contest was for Best Game or Interactive Experience, where the winner got 47.0% of nominating votes and 42.7% of final ballot first preferences, winning on the fourth count of a possible six."
The other finalists were Zelda: Tears of the Kingdom, Chants of Sennaar, DREDGE, Alan Wake 2, and Star Wars Jedi: Survivor.
A "save Karlach" DLC that takes into account all your choices during the main game... like, did you rescue the Gondians? Did you kill Raphael so the House of Hope is available? Did Tav and Wyll go with Karlach? Did you romance Karlach (I want SPICY)? I'd want lots more lines from Karlach and a frigging dancing scene with her at some point, because Karlach just begs to be danced with.
In my mind, the story would have to range all over the world, and we'd finally see the upper city and some of the other places visited in the previous games. Add in more potential companions, and some hard choices to make it interesting. I think my fantasy would basically make it into a BG4, so I know it'll never happen.
Tagline, "First you saved the world, now can you save your friend?"
Sounds like a contradiction in terms to me.