And the point with a game like 40k is the fluff is always evolving, and its rarely ever static for very long
I dissagree, the Fluff should be expanding not evolving, as in the old fluff stayed where it was but you add more rather than make the old fluff redundant.
I think I would prefer if the fluff was moved forward the world time and that the world wide campaigns actually contributed to the story lines. They do this in BattleTech and it has a very rich fluff history.