AI Races Expand Too Slowly.

[Marty Ward]

There is a mod that increases weapons platform range, Dev mod includes it. You should try that, PPB with range 12, APB with range 15. Tough to get close to a planet with this mod. Also, in the empire window you can remove the check mark to clear movement orders when entering a system with enemie in it.
As far as AI's being slow to grow I think with the number of possible starting conditions that the only way to overcome this is to have different AI files for different types of play, ie a fast expansion Version, a strong military Version, etc. but that would be a lot of work to make and set up.
I would guess that the most common set up is large mid-life and most people seem to play large quadrant so the AI should be based on this.