I always keep an eye on my players average position on the pitch during the game as I feel it gives an indication if their doing their jobs right. My problem is my two midfielders (I play 4-2-3-1) are two far (horizontally) apart, and I get the feeling this is not good for my team defensively. Does anyone know how I can get them to okay closer together? I have tried using the 'play narrower' shout but doesn't work.
I think first of all you should find out if your two central mid playing too far apart actually not good for your team defensively... watch the game in extended or full game mode for a while and see if their positioning actually causes problems, I play similar to your formation except with 2 strikers instead of Striker/AM uses standard width and never seen a problem with spaces between the 2 central mid (one defensive oriented/one attack), aside from narrowing your width though (which play narrower should do) I can't think of anything else...
Maybe they're too far from each other because they are too close vertically. Check if their mentalities are the same and adjust it so one of them has a more defensive role and the other a support role.
Another thing you can do is have one of them close opponents down more than the other.