Haven't received the game yet, but seeing some videos the only 3 things I will surely miss in the game are Radio Stations, fighting different people at the same time and not in TURNS! (Batman Arkham Assylum style) and more subtelty in the way you approach the assassinations (hitman style).
I guess if the game had all those it would be instantly GOTY.
I guess if the game had all those it would be instantly GOTY.