Should Larian keep a short-rest + short-rest + long-rest system.
I'm fairly sure they won't.
They clearly half-hated having to implement it in a D&D-based game, where it's supposed to be a core mechanic, and and it feels like they added it to the game almost begrudgingly (not to mention in a form that I can't honestly say I particularly liked, as it felt extremely artificial and disconnected rather than a natural part of adventuring around the world).
That's what happens when you remove the passage of time and a "tiredness" system and tie their absence to a rest that take place in a separate and instanced "pocket dimension".
I can't imagine them wanting to introduce something similar in their own custom ruleset.
Especially since they are already boasting in few interviews that they didn't like having to deal with the tabletop roots of D&D and they want to do something less focused on feeling an adventure and more on feeling "videogamey" (UGH).
It's the same reason for which I have almost absolute confidence their own ruleset won't include anything resembling interrupts/reactions.
We had to basically pry these out of their hands in Bg3.
