All those games have illusion of choice, like mass effect had nothing more, they just hide it better that there is no spoon.
To make game where choices matter you need bigger project than weekend one.
Minimal game with choices that kind of matter would be 3 doors and you die different way behind each of them.
I think you just want to make something bigger, not necessary 3rd person rpg, open world with meaningful choices.
So read about design documents, how to write that. And make very minimal for your game (just write down what type of game, what game mechanics you want, setting, artstyle etc. And then write down why all of this will be fun, why people will play it.)
Design documents are more for you than anything else, writing that down will let you se game from outside perspective. So if you are serious about making games (not weekend fun projects) start doing those, remember minimal ones do not spend weeks writing that.