Arioch and I noticed a bug in yesterday's build -- it looks like some of the AI factions weren't starting the game with space stations. That was badly confusing the AI, and making some maps far easier than they should have been.
I've just pushed a patch to stable that should fix the issue (r15388) -- but, be aware that games started using the un-patched build may have crippled AI factions. (I've marked any such games save games as "bugs likely".)