For once we agree.
I really don't think any more Civilisations should be added, the missing Civs that deserve to be represented would be in extremely crowded areas. I lived in Australia for years and I definitely didn't notice any real difference between it and the other Anglophone countries. Isn't it the world's only major nation to still have another country's flag in the corner?
On Civ respawns, I really think the Greek respawn mod should be added to the main game. It plays extremely well for the human at least. An Egyptian respawn-UHV would be very easy too.
The biggest flaw in RoC from the beginning has always been how dependent the human has to be on exploring for contact with unrealisticly distant civs. Roman tech-trade with China anyone?