im only realy replying here out of princle.
Im getting bored of the tired old nonsense u im afraid this echo chamber will grow even worse if theres not one or two people telling you youre full of shit.

They are not "reusing" the engine, they are updating t. Theyve been using this engine since Dragon Commander, maybe even Divinity 2 (which is not OS2 for the newcommers here)
Original sin was Verison 2, OS2 was verison 3 and this is version 4.

>on the technical side
idk. They appear to have built a very good network of interconnected systems, something very few RPG developers bother to make so if ail to see the problem here.

is placeholder. You dont start with Ui development when your feature set isnt set in stone do you?