In a recent Bell of Lost Souls article we were told that Games Workshop plans to de-synchronize their releases. This means that products will hit the shelves more or less as soon as they're released rather than being delayed so that they can appear with similar products all at once (i.e. Codex release).
What this means for us rules-enthusiasts is that we may begin to see more 'Night Spinner' style releases. A single rules entry written for a specific model release. This means armies will get updated over time (as well as having a codex for initial rules) allowing GW to release rules (and models) more quickly.
This could evolve into a system that rewards GW for every new unit entry that is released as each new entry can conceivably be used to re-vamp an existing army-list the way some Eldar players may have decided 3 Night Spinners was the way to go so too might others leap at the opportunity to refurbish large parts of their existing lists. This generates steadier, more reliable sales figures for GW spurring them to release more and more unit entries making 40k more diverse and exciting. There might yet be an "official" Rules Manufactorum supplementing existing rules with colorful, characterful additions that enhance the game.
Of course nothing is known for certain but we are seeing changes in the things are being run at GW HQ. They're responding to the community in a productive way and, if you ask me, it's about damn time.