Not sure what is supposed to be missing, unless you meant UC3.  UC3 was certainly better than average, and it has been growing on me, but I still don't think it is the masterpiece everyone seems to think it is.  It doesn't have the same lasting quality that UC2 had, and i think the fact that Naughty Dog split into two different teams is evident throughout the story and gameplay.  The only thing that really surprises me is that Deus Ex was the #1 digital sale, which is both impressive and completely fitting given the nature of the game.