Nuclear deterrence, legacy, genetics, the ethics and nature of war - the saga is densely packed with these kinds of themes, and could be too much to cram into a two hour film. For the most part, the series has focused on what we pass on to the next generation - whether that's in the literal sense via genetics, the cultural and philosophical sense via memes or the geographical, historical and political sense as a result of conflict. All of this essentially boils down to legacy, which I think is the series' silent theme and what the movie should focus on.