I can't cite many specifics, except that the combat just feels way better. It's simply funner to play. The cover system is vastly improved, and at least on PC, I could use almost all of my powers in real time instead of stopping to break up the gameplay. Depending on your play style this is either good or bad, but all powers have a very quick global cool down rather than a long one for each. So it's possible to spam the same power over and over and over without having to wait forever.
Dramaturgy is a study that helps make the world around the plot seem realistic. (i.e. time-relevant costumes or architecture in a historical film) Or... making sure that the Xbox is used properly.