I am hoping Larian does DLC that is entirely new modules separate from the main campaign. That's worth charging a significant price for especially for the multiplayer fans.
Larian hasn't been particularly huge on DLC in the past, at least by traditional means us gamers think of. Closest thing I can think of would be the gift bags for DoS2, which I wouldn't really say was DLC per se personally, as the original mods were already available on the workshop and nexus; Rather it was to port some of the more popular mods for console players to get in on a small portion of the modding fun too. Unless things have changed in partnership with WoTC, I'm much more inclined to suspect a definitive edition with more content and polished content based on how 1.0 went in player opinion, than extra modules added. (But it would be kinda cool to have post-content though, as long as it's additive and not cut out of the base game to be re-sold as "new content". But there's nothing imo to indicate Larian has gone down that dark path.)
So you are saying in regards to new - polished - modules we are more likely to get an entirely new game using the same engine than selling us a new module that can be added on. Or we need to look to modders to create that content.
And the expected Definitive Edition which will have new content.
This begs the question; is the majority of the work then creating the game story, maps, combat and dialogue or is it programming, bug fixing and modifying the actual engine?