FFG has published some great advice for GM on running the system and the setting.

Unfortunately, this advice is spread across a lot of books. Such as

The Nemesis section in DotDG

The Adversaries section (especially page 139), in CA

Life as an Acolyte (admittedly also useful for players) in the Inquisitor's Handbook

And scattered throughout endless, and always wonderful, sidebars.

Collecting this into one package would be unbelievably useful, but I'm not sure how copyright would come into this.

At the very minimum, there should be some index to reference where these rules and suggestions are.

What would be nice is a true FFG publighed GMs Guide to 40K style book, not just limited to Dark Heresy, but open to all three games. And not just monsters and cults and conspiracy, actual GM guide lines, suggestions and information.

what all 3 games? I know of dark heresy and rouge trader (coming out) what's the other? Space crusade or Inquisitor? I'm not sure if people are counting them as they were more a tabletop game.