I completed my first full campaign in AI War 2 a few days ago. It was a custom start with 80 planets on an Octopus map type against a single AI and no additional factions. I thought that I had set the difficulty to 7/7/7, but after losing the game I saw that the difficulty was only 5.
I took more planets than necessary early on, but maintained an AIP below 200 throughout the game until it was time to attack the AI home worlds. A massive swarm of ships spawned, and made a bee line to my home base taking out enough command centers on their way to give me a brownout.
I'm now about half way through a second attempt, this time playing the "Scenario 1" quick start. This time I will spend a few hours spending down my remaining hacking points before making a final attack.