-1 i would doubt that wotc would allow larian to implement subclasses outside of those established within 5e rulebooks, especially considering how larian apparently went to wotc post dos1 for the BG ip, didnt get it, went back after dos2 and got it - i just think that would be a bad business strategy and kinda a slap in the face to wotc and the BG fanbase if all of a sudden larian turned around and implemented a 'original sin' subclass which i dont even know mechanically how it would work. would the subclass be open across all classes? and what dos mechanics are you going to bring into bg for a subclass that will likely need tuning in of itself? i think at this stage adding a dos based subclass is unlikely and wouldnt be a good allocation of resources at this stage given other concerns.
(after reading my above post and thinking further, larian has added a bunch of dos mechanics already to a dnd game and apparently wotc is totally down with the games direction so who knows? maybe down the line, but i still dont think its a good game design - i probly wouldnt use a dos subclass, but if the number of dnd subclassses made available are limited then maybe i would try out a larian subclass self insert)