It's not fanfiction, though. It is canon, and is also the only thing to base discussions on.

Sure its canon but it doesnt really affect the game in any way. Now if we found a grimoire datapad inside a giant ahamkara skelton that was by a human skelton wearing the bones of eao and the arm exotic then that would be some cool environmental storytelling.

It affects the game as much as lore can. Any way that they can implement some kind of codex for the deeper lore is fine with me.

To me the affect lore has on a game is how you find it. Collectables if you will. It helps deepen your understanding of why a specific thing you are looking at is the way it is. Killing 1000 thralls to unlock the book of sorrow stuff is BS. (I know thats not what you do this is just an example of what the grimoire currently is) But if there is a specific mission that takes you through a hive library and there is some sort of puzzle that moves a bookcase on which you find an actual book sitting on a pedestal with energy floating around everywhere then thats affecting the game especially if you can take it as a trophy to display. The content of the book would be the same as the grim cards but the way you get them is magnitudes different. And then if this was a bioware game your character would then get new dialogue options and you could use that knowledge in conversations but oh well.