So, up on a random setting, I found some combination that will make Fallen Spire... Very !!fun!!.
First, make sure you turn on Nomad Planets. Somewhere in the campaign, especially at the worst time possible, one of it will drift by and create a shortcut for your nice little High AIP Waves, or CPA, or Exo.
Second, make sure at least one of the AI is Warp Jumper. Then, good luck trying to retrieve shards! (OMFG!!! THEY ARE COMING EVERYWHERE!!!)
Third and of course, crank Dark Spire/Rocketery Corps(No, I still think Neinzui shouldn't be making warheads) up to 11. This will definitely require you to break up your territory.
Currently I think the second is the most !!fun!! thing, because at least Nomads allow you to put a Warp Jammer and then act as a drifting scouting/bombing base. I typically choose one and put a Mod Fort up there, because if I lose one of these while connected to the AI Homeworld(Double CRE for extra fun)... Interesting things will happen.
I actually abandoned my previous FS game because Warp Jumper makes every defense virtually useless by sending waves from edge of my systems, by sending lots of Massive Ships from edge of MY systems, which makes things really messy when Shard is around my home.
It totally breaks defense in depth, yeah.