If the long run is predetermined, then it makes very little difference how I play this particular turn
But that is only because you assume the AI won't be a challenge. Don't assume that. Just play the game to enjoy it. Maybe the AI is toothless, but that won't become an issue until much later. Eventually the point in game will come where you for all practical purposes already won it, but that point will come no matter how good the AI is. In games like MOO2, it will come later. In games like elemental in it's current state, it will come sooner, but that does not stop me enjoying it up to that point, after which i just start new game.
And if i find a strategy that the AI is particularly useless against, next time i won't use it and try something new to challenge myself. For instance last time i made an 'old man' sovereign that had all physical stats total crap(5 con, 'clumsy' disadvantage ) and he never moved from the capital, relying completely on hired champions who brought him experience books and potions so he could level up. Stuff like that makes the game fun for me.
If you think it too easy, try figuring out a handicap that would hinder you the most, then try to play and win the game that way.(Next time i plan to research the adventuring tree all the way to top before anything lese to make the 'wilds' really dangerous
)