No multi feedback, but still:
(all the following experience is based on Standart difficulty Mrrshan. Yep, I don't like to overheat my brain=))
1) The other civs are HORRIBLY simple to rush. Just go for Engeneering->Physics->Whatever-you-like best, and at the same time spam Probes(until Eng finishes) then Marine Barracks and Invasion Ships. The AI never uses more than a single Marine for defence and usually hasn't established a second colony yet.... so it's a matter of one turn (and three-to-six ISs, as there usually are some probes/destroyers/scouts, all useless) and the race is down. That may be not the issue on harder difficulties.
2) Deriving from (1): the AI doesn't stand a chance with "Raging Barbarians" on. I have actually WON a Conquest victory WITHOUT attacking anyone (not counting the barbs, of course). The AI simply doesn't see the need to spam Marines(or Bombers. Or both) as I do, and then a Battleship-II-III comes out of the blue and no more AI... pathetic)
3) I don't know whether this can be cured, but still: could someone teach the AI proper use of Carrier Ships? I've seen the Meklar build a frightening fleet of titans, and not a single bomber or fighter based on them... and at the same time, they DEFINITELY nad fighters at their colonies.
4) Again, it may be the difficulty... but the game usually ends long before I get to the end of the tech tree, actually about the middle. Well, that's my fault - should have turned the Influence victory off...) IMHO, there are too many buildings giving influence...