Something that would make pirates more challenging...
A) shields + shield mitigation
B)Carriers + strike craft
C) 1 Cap ship at elevated, 2 at high, and 3 at Severe
D) hundreds of forces at their homeworld with hangar defenses an inhibitor and mines
.(Sorta like 7ds)(As to make it obvious that if you want them gone you're going to need to have a lot of spare forces to defend yourself)
For this to be balanced, it would have to take longer for them to increase their attack severity, and the raids would have to be longer apart, but with the addition of mines and star bases it should be more than manageable, and players could coordinate attacks with pirate raids to make them useful. I suppose with all of that more people would be inclined to acctually push the bounty onto someone else if they weren't turtling.