@RunsOnDiesel: Take a look at my starting army revamp mod, may be more what you're looking for.

There's no way to make the actual starting army a different size for a player or an AI. The only thing you can do is use events (which can be restricted to the AI) to add variably more things to their garrison pregame.

In general I don't intend on doing any more AI mods for vanilla dominions because I want to use my time on my Warhammer mod, but other people may be willing to.

Would you consider making a mod that makes the ai starting army 50% larger? an entire 2nd army seems too much.