I’ve found playing BB3, with its lack of story-driven missions, really highlighting how important it is for a game to have an interesting story progression. Otherwise, it becomes simply a matter of mission-after-mission. I found this as well with Pillars of Eternity: Deadfire. The game lacked one major story that you progressed along as you worked through the game. It had several different ones. But I missed being able to progress along one important, conquer-the-evil-threat story. PP has hinted quite strongly that there will be this intriguing story to progress through. Now, if you’ll just add a bit for BB4!!! 
It is very unlikely that we will add much of the story before release to avoid heavy spoiling.
Oh I know! Just wishful thinking. But in truth, I’d rather you kept it out! It’ll be much more enjoyable all at once with the finished project.