Just a couple of posts ago you said he makes many fouls, so perhaps you should at least get your arguments straight as now you agree he doesn't dive into tackles. Good in one on one situations, using his body well to block the ball, staying on his feet, great in the air, fast - are all those attributes and abilities really just one aspect of the game, or is that aspect what the rest of us call defending? Adding to that plethora of "aspect", his positioning is mostly very good.
As for communication, we have a problem in that we haven't had a settled defense since Rio and Vidic. Smalling and Blind actually formed a pretty decent partnership under LVG and seemed to have a good understanding. DDG, for all of his brilliance, still lacks command of the box and is too stationary leading to certain misunderstandings with all of the defenders.
Also, if you read the game well you don't have to tackle as much; subsequently, you give away fewer fouls. He looks to me as if he is pretty good at anticipating players' movements if he is good one on one. He gets caught out from time to time, as do all defenders.