Yay! I've been staying with the standard series but i'll give the expansion another shot now.
Few things I've noticed so far:
-Balance is FAR better. The replicators aren't invincible anymore. I was able to beat them outside their culture. However, when I faced a Replicator AI inside its culture I still got annihilated (I was an equal size fleet of Norlamins). The only way I see of beating the replicators inside their culture is to throw endless waves of bombers at them. Even then the default races don't stand much of a chance against them.
-Dangerous asteroids are still overpowered in the early game. They bog down initial expansion to the point of insanity.
-You still have the mass values reversed for the Norlamin Ship Mass reduction techs. Even though massreduction is green in the display info, it is still adding to ship mass (I blame this on an old bug in the game engine). In order for it to work properly, it should look like this: