One thing that seems certain to me is that the relative ability of a race as played as AI is quite different from their relative abilities when played by actual humans (single or MP). We know how to take advantage of things that the AI is just learning.
I am not too concerned though at the present state of things, as I believe the AI will continue to improve for some time. At the moment I still see common mistakes like colonizing a small planet in the middle of another faction's territory (thanks for the free colony ship!) and the AI missing some cheap shots. For example, I was testing for the black screen invasion bug last night (despite considerable effort I did not see it, which is good news) and clumsily left a transport next to an enemy colony waiting until the next turn. The colony had a ship defending it. Clearly it would have been easy for the defending ship to destroy the defenseless transport and return to garrison duty on the same turn. My marines were grateful, but not grateful enough to postpone conquering the planet subsequent to having the fleet that was supposed to be protecting them eliminate the colony defensive ship.
My point is that once the AI gets a bit better the relative strengths of the various factions may well change noticeably. Just a guess, though.
