i have alot of fluffy friends that are into this type of thing. i'm not that well versed in the cannon of 40k. i have played the game for over 20 years though...
that being said, the more the better. they talk alot about pre-heresy stuff and the astartes etc. frankly, i'd love to see some of these primarcs or even the emporer. that would lure me into apoc if anything ever will.