Much as I love the idea of being able to control your government, in all aspects (so far) you really aren't in 'control' of anything. That is to say, the humans are a vassal of their king, and the elves are still under the sway of the Council. I don't know enough about orc lore to comment.
However, if that were changed, or if you could become your own faction of sorts - that is to say, you are no longer a liege to the king, but a challenger of his throne, etc. - then sure, I'd be all for it.
Perhaps a benefit from conquering all of your faction, making yourself the de facto ruler of your race?
Regardless, Alpha Centauri had a great system as well as GalCiv2. I'm for having something like this, if only to make the game more replayable. I just hope that they actually work like political beliefs. If I'm a totalitarian, then diplomatic nations ought hate me.
...then again, do they have diplomacy at this stage? I suppose the elves might, but humans look feudal to me and orcs look tribal.
Sorry, rambling. But yes, that.
Arise, like the glorious phoenix!