[DirectorTsaarx]

I kinda like the idea, but I kinda don't. I'll have to say a 5. If the AI could be tweaked to go after homeworlds (especially if you're MEE), thus kicking off the civil war, that would add some thrill to the game.

I'm pretty careful to put population happiness facilities everywhere to keep the people Jubilant, so losing the Capitol Planet would be the only way to start the civil war. Seems like the AI has a bit more trouble with happiness, so the AI's would be breaking into war more often.

You could also add more Civ stuff to the idea of a capitol, and use the corruption factor (i.e., planets far from the capital have a production penalty). But again, that might harm the AI more than a human, unless the AI were designed to take that into account.