2 Things that would be pretty cool.

1) Timelines are cool. But they dont show the expansion rate of a race. It would be cool if at the end of a game you could watch a quick mini-map movie that only shows influnce. Something similar to that of the one in Alpha Centauri.

2) AI realising when a planet is a goner.
Example:
There was an Arcean planet that was no where near the rest of the Arceans. I had a fleet next to it. I would kill the defender. Every turn the AI would buy another ship just to make sure it wasnt defenceless. In alot of cases this is a good thing but when the ship is going to die, the AI is just wasting money.