The idea is lacking in game design insight and conceptual soundness. There's no strong drive for new mechanics, content, or otherwise that I can see in your proposal. If stapling the Pirate Factions to the existing militia is your proposal, why not just join an existing militia and not tie down developer resources?
All well and good.
So, how would you prefer such a thing be done?
Not at all, ideally, as the concept of any thing Militia related for the Pirate Factions scares the shit out of me.
There's one conceptually sound method you can go - have the Pirates fighting to take back their territory from the Nullsec alliances. That cannot be developed because it interferes with the golden child of EVE : the nullsec sandbox. It would cause too many problems with the established meta of the environment, as well as the developer's own perception of how it is meant to be 'left alone'.
The less sound method would be to develop a unique set of conditions for each of the Pirate Factions to influence lowsec instead. The Blooders are driven by Sani Sabik purpose and blooding motives; they can be rather pangalactic in their over all goals. The Sansha merely want revenge against the Empires, and although free-range Capsuleers are anathema to them, having them direct their carnage that way is useful.
Serpentis and Angels are ill-defined in ways that are conductive to galactic wide campaigns. They are the underworld of Empire civilization; they thrive in the illegal and criminal. The Serpentis particularly so; the Angels may have motives beyond that we do not know about yet. In that respect, though, they can be mainly based around stopping police activity. The Guristas are anarchists in general, so the Empires are a favored target, but their leader has a particular hatred of Capsuleers.
These are some distilled examples one could use to develop a set of victory conditions for each faction, and then build a system around it. Its not wholly accurate but it is 'workable'. Yet even in the workable state, it requires tremendous development resources to bring into a functional state for the game. Those resources could be directed to somewhere much more critical; such as a revamp of the corporate interface and starbase programming.
Even more detailed ideas I've considered for the 'Pirate Faction Warfare' thought strain I find distasteful and difficult to swallow. The one core idea that would drive them, retaking their territory in nullsec, cannot be realized. All others are just hamfisted inserts, and I think are much better not being considered in favor of more productive avenues.
