I agree that Entrenchment is almost certainly feature locked. Changing the way pirates work beyond whatever they've already done would require a great deal of testing and probably at least some rebalancing. Some of the stuff listed is very good, and I'd like to see it in the diplomacy pack, but we'll see what they do with Entrenchment. The rest of this stuff would probably go well in the third expansion pack, which doesn't seem to have a theme at the moment beyond "More stuff for everyone".
I don't know what they plan for that expansion, or even if they have a plan yet, but making pirates into an intriguing and potentially game shifting force would be very nice. At the moment, all they are is a nuisance. Find where they're likely to attack, throw a few cruisers and some LRMs there with some repair platforms, and even if you play without capital ships pirates aren't a problem after the earliest stages of the game.
Of course, a sense of self preservation and tactics, along with everything else listed above, would be a great way to expand their role. Plus, the option to create your own "missions" that the pirates (and potentially other players and AIs) could take would go a long way. It wouldn't even be that hard to do, considering the computer can already assign missions for you.
"Pirates have siezed one of your trade ports!"
"Pirates have taken one of your deep space mining platforms!"
"Pirates are demanding a shipment of parrots as ransom for your colony!"