I think it's almost guaranteed that Larian will make a new campaign with the same engine. I believe they said somewhere that they plan to use the engine for a while, and that would be a good financial idea for them. If they don't have to spend time and money developing an engine, they can spend that time improving that engine and writing and scripting new stories instead. What surprises me is the lack of improvements for the engine itself so it's even easier for them to actually create new content, which makes me wonder if they're trying to make a new engine instead, but I'm sure they have their reasons for delaying editor improvements.
I'm curious whether they're going to sell a brand new game, standalone game, or an expansion, or a DLC next. Probably they'll go the former route to get the most customers, and since there's not much of a reason to sell "expansions" anymore, given that DLC has basically replaced them. Perhaps we'll see a director's cut or GOTY version with a bunch of updates. There's tons of little things Larian could do to make the original campaign and the general balance a lot better, just like how the Shadowrun DragonFall Director's Cut really made the game a LOT better. Balance and content additions really made the replay worth it for me, and D:OS could do the same. And they might do a similar thing where the director's cut is free or at least super cheap for people who already own D:OS.
I'm hoping for a better story and writing. D:OS is definitely has above average dialog, but the overall story is kind of generic, even if has its twists. A less linear story and world would be wizard too, although I know that's quite difficult to pull off.
