Sorry to add to the fix pirates circle jerk just putting forward an opinion, i didn't see one of these suggestions mentioned with a quick search through forums so making a topic.
This board is filled with peoples suggestions on how to fix pirates, most of which unfortunately are people trying to put forward something that would mean either nerfing the pirate faction into oblivion or removing them (Temporarily or permanently) and replacing them with another nation. This is pretty ridiculous and there are much less extreme ways to fix pirates whilst also keeping the pirate faction a viable and enjoyable option.
As it stands the issue with pirates appears to be they behave like any other nation, with the same port mechanics etc. of any other nation, however they are also a very popular nation so have overwhelming numbers over others, and as such are expanding way too quickly, pirate players can also attack whoever they like, including each other and aren't as restricted as the rest of the factions.
I might have misread the situation but from my perspective the issue here seems to be that pirates are way too coordinated and way too strong so rather than their presumably intended design to be a smaller, more challenging nation that is suppressed by the big powers (Great Britain, Spanish Navy, US Navy etc) . they have turned into a "Super Nation" and have taken over way too much of the map than they should be capable of.
An alternative way to fix the faction, a more preferable one for pirates than being nerfed into the ground or having their ships limited to only crappy privateers etc. Could be two things.
1. Do not make the Pirate Faction joinable as a new Character (This has already been proposed by a few people and appears to be a good idea), Make it so that people must first join another, regular Nation then can only become pirate by attacking a friendly faction member, making it less appealing for players to immediately join.
2. Remove the Pirate Nation Chat, it seems kinda odd that pirates should have a communication network as good as GB, US etc, they should be far more rag-tag and divided than they actually are, by having the Pirate Nation chat it is far too easy for clans to expand are become very powerful and for these coalition type deals to be formed which makes taking ports and defending them ridiculously easy with a nation with as many players as pirates, This doesn't mean completely removing communication between pirates and clans ability to recruit and communicate with each other, there should still be Port chats for trading, clan chats and friend chats, therefore pirates would still be able to group together etc, trade at ports and all that. But also be less coordinated than the big powers in Caribbean waters.
Both these seem like more reasonable suggestions than hardcore nerfing Pirates in some of the others ways people have come up with, it would make pirates more at odds with the other nations and also change them from being a Super Nation that has the same default politic system as other nations, with the added bonus that way more people join pirates than the other factions because the pirate label is cooler, to being a smaller, less coordinated less conquering faction more focused on raiding, ducking and weaving between the big factions navys etc.
Just my two cents, make up your own mind on it.