The Diplomatic AI strategy is truly horrid.

It kicks in around turn 30, and the Thalan and Terran factions ALWAYS use it from when it becomes available (except when in war). The AI will adopt an 80% research spending, 10% manufacturing , 90% social manufacturing focus. This is happening before the AI has built everything on it's planets, so it never manages to finish building up it's worlds; it gimps itself automatically.

On top of this, the 10% mil spending means that AIs using this strategy are only spending an effective 1% of their (already gimped) output on military construction. This means that they not only won't build up their planets, they also won't be getting any new colonies any time soon.

Now, I think that this is a horribly balanced strategy, but I'm concerned that the locked-in nature of the strats is a bug; I would have thought the AI would switch between the various strategy options that were available to it rather than sitting on one. Both Terran and Thalan factions should be eligible to use ExpansionStrat if they weren't constantly on Diplostrat. Combined with the fact that Aggressive_strategy_general never seems to activate for anyone, I suspect that the way the AI picks it's strategies is either bugged, or horribly imbalanced.

All credit to rspiccaver for finding this.