Depending on what the Galactic War ends up being, or even for any very large multiplayer games, would it make sense to have sort of a custom AI controlling different aspects of your game, or providing an option for advanced unit orders to maintain the more tedious components of your vast empire? Especially say for economic development in something like Galactic War mode where it could be very daunting to manage the larger your empire gets. Providing those types of effective empire management tools is something that most, if not all 4X games lack, and they generally suffer for it in my opinion. Most RTS games don't require them due to their smaller scope, but PA looks like it will be an exception. I'm sure that Uber has considered this long before this post, but I would love to read their thoughts on the matter.
Build templates would be a good thing to have here. have a few standard expansion templates and tell an expanding engineer to use one and come back when the base is established Maybe have any new engineers built at that expansion help the original in order to speed production and include automatic patrols for units built at said expansion's factories and you've got a good start.
I assume this would be something similar to the Dawn of War campaigns. So no real AI required at that level.