Well, what to say here. I guess people just lost interest to play as Corsairs. Playing some faction is a complex thing, it includes the interactions with other players, not just cool looking ships or so.
Let's see what Corsairs can do at the moment.
1. Pirate. But there is too much money in the game already and not many people keep running the trade or mining. Cash grinding was a way too easy so the cash flow was too fast and thus the interest to the mining\trading got exhausted too fast as well. Also trader behaviors are cool too (I know it's two edged sword, really). I guess both traders and pirates got annoyed one day by own assholery and just not motivated to bother with piracy when you can simply pew with navy or so. Also I didn't noticed any significant traffic between Bretonia and Rheinland so nothing to catch anyway.
2. Go to the hostile territories to fight\pirate. This includes 3 general directions.
2.1 Bretonia. Well, honestly there was always a lot of mutual OORP dislike between Bretonia and Corsair players and I, myself, one day found I don't want to go to Bretonia because it doesn't pays out. We're playing for fun and I see no fun in Bretonia. Bretonia players managed to fail in providing any sense of healthy gameplay to anyone hostile to their lawful factions so I'm still staying away from there.
2.2 Rheinland. Once upon a time it was a cool place and I spent a lot of time there with many factions. Corsairs, RM, Unioneers, Hessians. It was a nice and friendly place with cool people to play along or to pew with. Now it's just a land of frustration and depression. In short - Bretonia mk 2. I don't even know at what direction I have to send the blame. Just one day it turned from good place to play into the swamp of constant ganks and oorp hates.
2.3 Outcasts. To raid outcasts you need people who likes to fight and raid and you need people who likes to be raided and ready to defend. Both lacks on both sides. At the moment people are too obsessed with RP part of the game forgetting that another half is a pew arcade in space and that results in constant whines about the raids, ganks (because it's RP to gank, y), oorp hates and other bullshit. Also recent changes to the systems are not of a help at all. We were promised that Sigmas will be a "paradise" and alive again like it's 4.84 back. Wow, failed completely. No wonders though. I already expressed my feelings towards the developing methods generally and lack of any gameplay planning and control partly.
Those are the main reasons I think. Really, guys - stop to assume that the core of a problem with activity is some stupid "balance" or "bad ships" or lack of caps in the ship line, or so. It doesn't matter in the end. We log into the game not to observe the pretty ship's butt for a hour or so. We log to play with other people - if there is nothing to do or the said people are dickheads no one would log since there is no fun to catch.
P.S. Also I want to repeat myself a bit, but I want to send a beams of hate towards the people who likes to change the jump hole positions every damn mod version. Stop please, really. This is fucking ridiculous and not freaking funny. It was okay even in vanilla. It wasn't broken. Why you ruin the damn jump hole network. Thanks.
P.P.S. I logged now my old Legionnaire (that old mk 1 sair LF, from vanilla yn. I had one.) And it have a Class 10 missile slot, mines, cd, cm. (bandit) pretty bug, but let's what can be done with that ship (bandit).