Just a thought on the Pirates, what if you gave them their own little world, with something minor for income and their only ground building is a super powered cash multiplier to feed them. Then, let them build a fleet, with the bulk of their smaller ships being set as infiltrators so they can move mostly undetected. Leave them with a few larger ship options so they can build defenses too, but set their AI to favor the infiltrator units for offensive
I don't like this idea. Why?
They are criminals more powerful than galactic governments.
They have loads of money.
They are as powerful with one planet as they are with twenty-four.
They have stealth units that can go right past your fleets and attack you anywhere. You can't do anything about this except defend all your planets equally.
This isn't as severe as the Consortium but I could still see it being frustrating.
It's also not that interesting to defeat them. The AI is terrible at constructing elaborate defences and will instead spam whichever unit it likes best. Do you have any idea how boring it is to mow through two hundred squadrons of E-Wings? It's basically
this.