A new FAQ for the Space Marines had dropped today. This shakes up some of the more powerful Chapters and units in the game.
I think most people can agree that the Space Marines have been dominant in the game since the release of the new codex and supplements. These new rules are an attempt to address some of these issues, let's take a look at how they are doing.
This is a huge change for the rules and will have a big effect on a number of armies, most notably, the Iron Hands, who have been using the Devastator doctrine to very good effect.
Space Marines now have the Devastator doctrine in turn 1, the Tactical Doctrine in turn 2, then in turn 3 can choose the Tactical or Assault Doctrine, and the Assault Doctrine from turn 4 onwards. This new rule forces players to move through the Doctrines, so they cannot stick with the most powerful one for their army for most of the game.
This is a big counter to the power of Iron Hands and Imperial Fists armies that were very powerful in the tournament setting. The ability to move and fire heavy weapons without penalty, as well as re-rolling 1's to hit was a massive boost for the firepower of Iron Hands armies in the game, getting this ability from turn 1 for the whole game made them one of the strongest armies in the game (in combination with a number of other abilities).
Now, you get one turn with the bonus to your firepower, then must move into the Tactical Doctrine. Additionally, the Tactical Doctrine has become slightly less effective for the Raven Guard, as you can only get the bonus for a maximum of two turns.
This actually makes armies that have a doctrine bonus in the Assault Doctrine a bit more powerful, as this is the doctrine you will be using the most in games. Depending on when you switch the doctrine, you have to spend around 50% of a standard game in the assault doctrine, or up to 70% in a seven turn game.