You've mentioned some very good points what an rpg should be about
The first mistake anyone can make when critiquing a game is to dictate what a game "should be about", at least in terms of "All games should have this type of plotline".
RPGs don't have to be "big". They can survive with minimalist plots or ones about tiny insignificant lives. They DO, however, have to make you care in some way.
Gaia a Search for Eden, as an example, wasn't about saving the world or stopping some great evil (In fact the game punished you for thinking of the game in those terms). Yet it sucked you in through its grand narrative.
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And yes Divinity Original Sin 2 has a HUUUUUUUUUGE problem with making you care for the most of the opening.
It relies on gamer mentality to carry it... a thought that "Hey, I don't deserve to be in jail!" even though you have no reason to believe that.
The desire to destroy Dennis... even though all she did as a nondescript villain was kill some official who did something we don't really care about.
With the guards not really harming us... and the people in the prison being far more of an obstacle.
Then... when you solve the problem you are once again without any motivation and are searching the island purely out of gamer mentality.
Hey Remember Chrono Trigger? Remember the part of the game where Crono had absolutely nothing to do or any goals? No? That is right, you ALWAYS had some sort of motivation...
Didn't that game have a jail section as well? Notice how you had an immediate desire to escape due to the whole trial scene?
For all we know... we murdered a bunch of people and got thrown in jail :P We don't know.
