well, your saying storywise, the game itself is progressing in a direction .
I'm saying, sure, great, but that only makes any sense at all if youve kept up with the game since wayyy earlier.
However, if the game had some landmarks where stuff got interesting.. like for 2 hours, the game is 'just' base ai war... then suddenly you start seeing zr stuff, possibly randomly get a golem thrown at you, you start seeing the trader/mining/devourers/dyson etc.
around the 4-6 hour point, CoN stuff starts appearing, neinzul waves, roaming enclaves, etc, and the ai starts replacing turrets with guardians
Similar to how in <insert rpg here> as your character levels up, you face harder and harder bad guys. Specifically, in Fallout 3, its kinda hard to play an energy weapons character until you hit the enclave at PP, but once you do everything becomes almost easy.
then again, my FO3 is modded to hell and back to make it considerably more difficult in the beginning, but the theory remains similar