I noticed a change recently where if you capture the capital colony of an AI civ, the Civilization Capital improvement becomes an Initial Colony improvement after you make the capture. Another colony of that AI (it seems almost random) then becomes their new capital. If you are on a rampage to capture every last planet, the LAST colony you capture remains a Civilization Capital after you take it (and remove that AI race from the game).

I don't really like this new logic. I DO like the fact that you don't see captured Civ Capital improvement all over the place, as that became rediculous if you captured the AI's planet in the right order (always capturing the new capital next).

I'm proposing a couple changes:
- If you capture an AI capital, the planet will have a Former Alien Capital improvement on it, which has bonuses that are somewhere between Initial Colony and Civilization Capital.
- If a race (yours included) loses their capital, they have actually build a new one! No more getting a free capital as a reward for not properly defending the old one. Make it expensive too. Perhaps around the same production cost as an Industrial Sector.
- If a race (yours included) is currently without a capital, there should be some negative modifiers until they rebuild it.
- Even if you capture the last planet of an AI civilization you don't get to keep their Civilization Capital. It becomes a Former Alien Capital also.

Just imagine if Washington D.C. was destroyed somehow. You would lose your seat of government (the important symbolism and the physical buildings), as well as all the high level bureaucratic offices and infrastructure. There would be no choice but to build all that ASAP, and it wouldn't be cheap! If you wait, the rest of the nation would be without proper leadership. I'd like to see something similar modeled in the game.