Join Date: Aug 2009
Location: Portland, Oregon
I think a television series following the adventures of an Inquisitor and his or her scouring the Imperium for heresy, aliens, and mutants would be good. Something like the Eisenhorn series.
Not everyone is in the military. Not everything revolves around combat. I think this would be the best shot at getting some more mainstream attention without delving into unknown fluff territory (aka, making stuff up to satisfy the general population), yet at the same time appeasing fluff readers like us.
I don't think a super grim-dark series would work. Then again, dumbing it down to where all the heroes get to live every day even though 99% of their comrades manage to stop a bullet somewhere in the movie/episode seems a bit... ungenuine for the setting (not that it doesn't happen, but I'm still sad when it does in BL).
Once mainstream appeal is reached, then niche stuff (following aliens, an Imperial Guard regiment, etc.) can be met. More people might be willing to take the dive and check out the rest of the universe when they realize the pool isn't as cold as they initially thought.