Cities...

They have art for Settlement, City, Metropolis and Megopolis (City uses this atm), so they thought about it at some point. I added a chain for GST, 2, 4, 8, 16 pop.

With smaller steps (not 9 or 16 population per 1st level city), morale management would get much easier. I think it would be healthy for the game to have at least one more level. Maybe +4/+9 for silics and +8/+16 for carbon and aquatic.

I agree, there should be at least one more level for cities.

I'm currently testing a mod that adds Settlement, Town, Metropolis, and Megalopolis improvement types.  Instead of replacing the City they are in addition to it so that I don't have to update the game's ImprovementDefs.xml.  Settlement upgrades to the others with additional food or Durantium required.  The way I currently have it is that Settlement gives +4 population cap, Town an additional +4,  Metropolis +8, and Megalopolis +8, so that doing all the upgrades will get you +24 on a planet.

Over the weekend Brad has been making changes for a 2.3 release that may require me to take another look at these values.

That would be a nice MOD to have if the 2.3 update does not take care of it.

This is what Brad said he'd done for cities, for the next patch (eta unknown, although he said this week):

City population cap reduced from 16 to 9.
City food cost increased from 2 to 3.
Cities provide +2 level bonuses to Research, Manufacturing, Wealth and Influence improvements!

So I can update my mod to add the level bonuses and rebalance the food costs, what do you think about the population caps?  Do 4, 8, 16, and 24 still seem good given that a City will soon provide 9 instead of 16?

I think your mod is heading in the right direction.

Question back to Brad's comment (and I know you might not know the answer)...

" Cities provide +2 level bonuses to Research, Manufacturing, Wealth and Influence improvements!"

I love it, but would like to understand:  Is this an "adjacency bonus" or a bonus for coexisting anywhere on the same planet?

I believe it's an adjacency bonus.  We'll have to wait to find out for sure.

Must be adjacency bonus since a facility that provide planet wide bonus never exist.

Unfortunately, for those of us who like to play synthetic,  it seems like just another advantage for "flesh bags". 

Quoting Moser_Alchemist, reply 10

Unfortunately, for those of us who like to play synthetic,  it seems like just another advantage for "flesh bags". 

End of Moser_Alchemist's quote

True, a potential solution would be to give synthetics a higher bonus from Capitals (even 1 higher than the filthy biologicals would be nice)

OK, new mod up: http://www.nexusmods.com/galacticcivilizations3/mods/113/?

I may need to tweak it after the next patch comes out.  Also, I might add support for Financial Cities, Manufacturing Cites, etc. if people want them.