Good to see positive reviews, especially for a turn based isometric RPG. But Larian needs to patch the shit out of this, add new DLC and call it enhanced edition. CDPR has shown the value in a second release.
For this kind of game I think they'll get more mileage by polishing up and supporting the editor. I'd say wrapping the toolkit up is the only thing that is really needed besides the patch that will be coming soon with companion AI, etc.
There are some balance changes all round to be done aswell. Dificulty gets realy funky after level 10 or so, normal mode dificulty kinda gets into easy mode and the game seems to artificialy try to counter this by adding artificialy created miss rates for melee and pets wich seems weird. Dificulty should be ramped up through increased enemy HP/damage output not funky behind-the-scene math calculations.
There are aswell some UI changes that would go a long way to make the game more accessible to people with less patience, but still maintain the "hard-core" feeling for veterans - there are numerous sugestions already on the forums, mainly on inventory and journal UI.
Also, the "gigantic/endless/watever" hardcore dungeon that was promissed in KS would go a long way to create a new flavor for the game that is already quite rich. Day/night cycles i understand it's way too big of a change to make it a patch or even a DLC and quite honestly it would introduce too many changes to the game that already works realy way the way it is now.
Also it's realy needed more variety in the companions. Only being able to pick the same 2 realy cuts on the replayability of the game. In a game so vast and "open ended" as D:OS it's realy weird we can only pick the same 2 companions in the entire world, it feels like a cutted feature (yes i know you can pick more, but they are just dummies with no lore/background story - not the same. Surely larian will add more.
All in all, one big patch is needed to add more companions (with their story/lore ofc), new AI personalities, balance fixes at end-game and probably a few in the starting 3 levels (to make it easier for entry-level newbies), some UI improvements and toolkit easy-to-use changes.
After that, i'm all for new adventures and DLC, even an expansion. Larian please take my money, i dare you