I was never into Warhammer (past or future) mostly because I was shackled with a tiny wallet and the painting skills of a blender, and all the measuring sticks and templates were intimidating. But Space Hulk was quite nifty, because I didn't really have to know what anything was in any greater scheme. Just that these dudes hated those things and vice versa. I never got to play with the Space Hulk expansions, but I did see them a couple of times in play, and I got a bit of a sinking feeling that Games Workshop was trying to wedge some of the larger Warhammer concepts into it, obviously to feed the target audience. Kinda fell out of the whole thing entirely.
But I loves me some co-ops. Getting a little ravenous for it now that I've awakened the hunger in a few others with Arkham Horror. My concern is that buying this first issue of "Superman" isn't going to mean having to read up on a few years of "Justice League" so I don't feel like I'm missing out on anything. (A few of my AH buddies are like that; one of them is actually reading Lovecraft as we speak.) Warhammer chronology has never felt like so easy a topic to just "read up on"...feels more like a multi-year college major.
Of course, I'm probably jumping the Storm Bolter something fierce here, so feel free to tell me to shut up, wait for the game, and don't worry so much.