Am I the only one who is in no way interested in a catch-all 40k book? I like games having a narrow, specific focus, and I think trying to do too many things would just mean it'd end up doing a lot of things poorly instead of a few things very well.
The problem being that the seams start to tear when you're doing crossovers, which is a very, very, very likely thing that you'll be doing one way or another in the 40k universe.
The vast majority of the rules are already interchangeable. A unified ruleset would just exist as tear-prevention, so to speak.
Narrow focuses to accommodate the facets of the galaxy would be what all the supplemental Campaign Scenarios would be for.
Edited by Fgdsfg