This thread is for people to post any observations they have made regarding how FM13 differs in terms of tactical implementation.
This is not a place to ask for tactics or to discuss whether certain tactics work.
I believe Raikan and TheBetterHalf already have plenty of those threads in place for now. In other words, it is not meant for discussing specific tactics. It is for general observations about how the match engine differs in implementing our tactical decisions.
For example, the first major thing I've noticed about FM13 is that player roles have a much higher importance. In FM12, you could get away with both your CMs set to "Central Midfielder - Support" and just alter their player instructions so that 1 played slightly more attacking / defensive than the other. Now this does still kind of work in FM13, but it leads to a lot more short passing back and forth in midfield from my experience so far. In order to get that flow from defence to midfield then pressing on to attack, the combination of a Ball-Winning Mid (I set mine to defend) and a Deep-Lying PM (set to support) works much smoother. Now obviously, you may not be playing the same type of football as me, but my main point is the importance of player roles has been hightened when creating tactics. That's the kind of general observation we're looking for here, which can help others put together their own tactics easier.
Also, touchline shouts seem to be much more important too as AI opposition does seem to switch their play depending on the situation. If you take the lead in an away match, for example, the opposition will go noticeably more attacking and you will NEED to compensate for this. You cannot simply plug and play tactics for every match like you could on previous versions.
I know these 2 points I just made are kind of obvious, but they're just examples really... hopefully we'll get a lot more in depth observations as people get deeper into the game then we can take the points from here into the tactical discussion threads where we can design tactics keeping these things in mind.