I'm definitely not seeing the AI sit on colony ships if it can colonize. It's been hyper aggressive for me. Odd? Maybe people should list the settings they are seeing this on.
I would advice you to check which personalities your custom races have. From my experience races that follow Drengin and Yor behaviour are the strongest. They like seen quite a number of tests and tunes pre-release. Some other personalities may be weaker by far. Normally the less popular is the race among fans and devs the weaker it's AI. I remember Drath Legion and Arcean Empire always playing quite poorly.
Overall the game still needs a ton of fixes with the AI specifically. Let's wait and see for the 1.1 patch to come out.
I don't believe this is the problem at all. The three races that have performed the strongest in my limited number of test games.
Krynn, by a long shot, followed by the Yor, and then the Altarians. The Drengins tend to be in the bottom half, whereas those three tend to be in the top 7-10, with the Krynn frequently in the top 3.
Looking at the AI priorities, the Krynn do not have growth or expansion as one of their dominant priorities. Growth is 5th and expansion is 6th. They do however have aggressive and expansionist traits. If we compare to the Yor, aggressive and scientific with growth 4th and expansion 6th. Their racial abilities? Synthetic and Adaptable. A solid choice for early game expansion obviously. While the Krynn are prolific and zealous. I'd say that without question prolific is the most important early game expansion trait for the AI followed closely by fertility for any organic races.
I honestly have to question the settings. I've never seen any race sit on colony ships if it had planets it could colonize. Have you actually checked to see what these AI factions could in fact colonize?
I'm looking at a game with the FOW turned off that was played to turn 100. It was a loose cluster game with the same settings I mentioned in the other post. The overall civ power rankings have;
2. Iconian Refuge.
3. Krynn Syndicate.
5. Altarian Resistance.
6. Yor Singularity.
7. Drengin Empire.
The Thalans and Terrans are 18th and 19th respectively out of 20 AI factions. I can instantly tell why looking at the starmap with FOW disabled.
The Terrans have colonized 5 planets. They started at the edge of the map in a cluster that had 5 colonisable planets and then a band of empty space 40-50 hexes(parsecs?) wide. By the time they could reach anything else they were clearly already taken.
The Thalans have 4. They spawned in sort of a middle ground, but they face the same problem. On one side of them were the "Raas" an industrious, fertile, reptilian race with prolific as a trait. On the other side, is a vast expanse of dead planets, at least 50 parsec's deep.
I'm not saying the AI isn't doing as well as it can, but I think we need to exhaust all explanations before we say it's broken. Clearly it isn't broken when the Krynn, Iconian Refuge, Altarian Resistance, Yor Singularity and Drengin Empire are all capable of gobbling up 30+ colonies inside of 100 turns.
I firmly believe that the biggest cause of lack of colonization, is lack of opportunity to colonize. What size map are you playing? What star formation? How many AI? Do me a favor. Run the biggest map your computer can comfortably handle. Use the scattered star systems style, and set pirates to rare. Now just click end turn for 30 turns. Hit tilde, type FOW and then see if anyone is struggling. Then see if you can tell why. Reload the game, hit end turn for another 20 turns. See what it looks like at 50 turns, then at 75, then at 100.
If anyone is sitting on colony ships with very obvious opportunity to expand, then there is clearly an issue, if races are sitting on colony ships and they have nothing to colonize, then that might be the cause of what you are seeing!