What does this mean, besides a new way to extend the releases for each race?
First off it was spectacular that Games Workshop did not wait to publish these, and seeing one in the same month as an army codex release is nice. Of course it means that Games Workshop can push the envelope regarding its releases, and increase sales for those players playing each codex. I can easily imagine now how new chapters of marines might get their own supplements.
What I like about it is this, it helps really expand our game in new directions, giving us more detail, more special units, and more options to field on the tabletop. This will help increase the number of different units and combination army types that we will see on the gaming tables.
While I am sure there are many that will just say its one more way to cash in for Games Workshop, but I am going to say that I think this is a good move for our gaming hobby. There were many people that were concerned and disapointed when Chaos Space Marines did not handle the traitor legions well, and lumped all of Chaos Marines into one dex. Now we have an answer from Games Workshop, and we should be happy about it as our hobby will begin to expand beyond what we had first anticipated.
I will be eager to see this supplement, and the future of how these supplements will effect our hobby overall.