Boris Gudenuf
Deity
A case can be made for a 'fleshed out' Piracy mechanic, but not, IMHO, for a 'Universal Piracy Path' for all Civs and Leaders without, as posted above, some potential severe Diplomatic/military penalties.I disagree. First, unique, defining features of a civ given to everyone invalidates the civ in question very quickly. Very few nations in history considered piracy as something to be supported, or even tolerated. Piracy was also only a significant issue in several specific historical and geographical epochs. And, if a nation was caught engaging in piracy, it WOULD cause a massive international, worse than just a sneak attack under their own flag - but you portray a situation where such a discovery would never happen, and if it did, would be guaranteed no consequences. That is VERY wonky, indeed.
First, although piracy historically was limited in time and place, there were significant piratical influences at widely separate geographical areas and in all of the game's Ages.
In Antiquity Age, throughout the Greek world pirate coasts were to be avoided, because piracy was virtually omnipresent and the piratical factions were so well-organized that ransoming prisoners from them was a regular business accepted as 'common practice' among the civilized nations of the area - until the Roman Empire took control of all the coasts and used that power to crush he pirate factions (which, in game terms, would be IPs unless they give us Illyria as an Antiquity Civ, which would be a real stretch)
In Exploration Age, Southeast Asia and the China-Korea-China triangle of coasts were swarming with piracy, and some states in Southeast Asia could make a better claim to being 'Pirate Kingdoms' than anybody in the Caribbean - they were larger and more powerful and lasted far longer than the Baconneers did in any form. Piratical actions were also, again, common throughout the Mediterranean but as Official Actions by Islamic and Christian states against each other. This is the one time and place that Piracy might be acceptable as a Civ Choice because it was such a universally acceptable practice between States on both sides of the religious line, but it would require a relatively narrow set of circumstances to make it work.
Modern Age of course, has the pirates of the mid-16th to late 18th century who acted not only in the Caribbean, but everywhere in the world that shipping went - the greatest pirate haul in history was in the Indian Ocean, where Henry Every (Avery) got away with the Mughul Emperor's treasure ship taking rich Mughuls to Mecca for pilgrimage - think Mansa Musa on the water loaded to the deck with gold, gems, and luxury goods by the ton. But after the 18th century, piracy becomes a strictly IP action by private groups from areas with weak or non-existant governments - government action on the sea becomes strictly a matter for regular warships and their crews (including especially submarines) rather than private individuals and crews, and pirates caught anywhere can expect short shrift from everyone - not the multi-national warship collections doing anti-piracy patrols off Somaliland when [irates became a problem there.
So, there are only specific times and places where piracy is appropriate as a Civ Choice, but piracy as an IP choice is much, much more common. Also note that the most common piratical action for most of history was not raiding ships but raiding the coasts: attacking small towns, villages, right up to major cities if you could gather enough ships, because, after all, towns were where the loot was already gathered for you if you could get to it.
I suggest then, based on historical examples, the following might be a basis for Piracy in the game:
1. Only certain specified Civs can perform piratical actions without going to war.
2. IPs as Pirate Factions should be much more common in all Ages.
3. Anybody who fights pirates will get major bonuses in diplomatic points from every other Civ or IP that is not Piratical. This could be something as simple and general as destroy a pirate vessel, get X Influence Points. Destroy Pirate Faction (IP, Civ) and get some positive bonus without spending any Influence at all for it.
4. All pirate vessels should be able to raid coastal tiles - and a special Viking Rule might be that they can raid up to X tiles from the coast since they were notorious for landing, stealing horses and riding well inland to raid before riding back to the coast before they could be intercepted.