I think custom races are handicapped compared to the canned races owing to the larger number of points assigned to abilities. I recently played a game with my custom race against all customs on crippling. For quite a while, the MINOR races were the top civilizations in the game. Something just isn't right when the Jessuins are the No. 1 most powerful civ. That this situation could arise outside of some sort of mega event is crazy. By midgame, I was the only player who's economy was not in the toilet. The AI can't seem to make the custom races thrive even if you create a custom with abilities similar to the AI type you assign to it. I love the idea of making custom races. It could really spice things up. But as it stands, they aren't competitive outside of player control.
Its a mistake to assume that the minor races are inherently incapable. If you look at their stats in the data files, some of the minor races are quite good. The Jessuins and, especially, the Akillians are among those. BUT...minor races inherently cannot colonize (its for gameplay reasons, but rationalize that it is just part of their alien psvchology). Because of that, they fairly quickly fall behind in research, and in defensive ship production. Also, their limited population limits their ability to expand by invasion. Let one of the minor races get that special event that allows their spies to steal the entire tech knowledge base of a leading race fairly well into the game and they can become quite formidable.
Recently I finished a game in which for the last third of the game the Akillians were clearly the 2nd leading race (partly because I was helping them behind the scenes).
I didn't want to waste time being at war with the ramaining major race, the Drath. But the Drath had foolishly declared war on the single-system Akillians. The Akillians had already earlier in the game stolen the Krynn tech base, before the Krynn had amalgamated with the Drath (under pressure from me in our long standing war), so the Akillians were no pushovers in any case. So I stayed friendly with the Drath, with occasional talks and minor purchases of influence points, while trading / giving a series of advanced techs to the Akillians, and, especially, fully loaded super-transports. Funny thing, if you give a minor race a big transport sitting within 2-3 squares of one of their enemy's planet right after their roving battleship has waxed the orbiting defenders for fun,...the minor will invade with it. By the end of the game, when I inticed the remaining Drath system to join me gratefully for a Diplo victory, the Akillians had about 9 planets! (It was an All Rare, Gigantic, Obscene configuration.)
drrider
