As an American, with how often this happens I have to just assume the US accent is just easier somehow than the others. Because similar with Chris Hemsworth. Watching him in Furiosa just felt weird because he was finally using his normal Aussie accent.
See also: Hugh Laurie
But for real, Toast of London is a treat, and it includes heaping helpings of our friend Gale.
A Planescape area/sidequest, just make it so far out there and weird, but let it have almost nothing to do with the main plotline. You find some random portal that dumps you there and it's just this weird sort of thing you get into that you never talk about again afterwards.
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?"
Officially supported versions of stuff I enjoy from mods, like more subclasses from Xanathar's, a properly working werewolf model for Blood Hunter mod, or stuff from TCoE