[Noble713]

I've been invaded by the AI ONCE. It was in my current game, actually. I had taken a system from the Terrans but wasn't willing to disperse my fleet to cover every planet, so they slowly came back and glassed several of them. I was quite surprised when one of their fleets came with a medium transport and dropped a mere 7 large troops on one of the planets.

So yes, the computer does use the VERY few troops that it builds, but certainly not often enough. I think the problem lies in the AI_Construction_Vehicles file. The computer is set to only build 1 troop per planet and 1 transport per 10 planets for the Infrastructure setting, and for the Attack and Secure Holdings settings, troops and transports aren't listed at all.