Navy Playstyle
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Disadvantages:
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- You should at least sink X pirate ships per X months else you get demoted or fired
Bad idea. For one thing, you've already said that there won't be as many pirates. In fact, if you're doing your job really well then there wouldn't be any! Also, ships belonging to enemy nations ought to count - and again, if you're doing a good job then they're going to be rare, so you won't find them. You get demoted because you have done too well and swept the sea clear of His Majesty's enemies.
Merchant Playstyle
Advantages:
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- Only pirates will be enemy with you
- Crew morale when hirering them will always be good
Pirates are not your only enemies. Merchants also need to fear warships belonging to enemy nations. Commerce raiding has been a valid war strategy for a very long time!
Why would crew morale always be good upon hiring for merchants and not for others?
Disadvantages:
- Hoisting a false flag will get you kicked out
Why? Hoisting a false flag to get past enemy ships is perfectly valid. I know for a fact that merchants did it during WW1 and WW2; they probably did it during the age of sail too.
As a merchant, you should not be allowed to
attack anyone. You are, however, allowed to defend yourself. The only way to handle that in game is probably to penalise you for firing on anything which isn't hostile to you, but both pirates and enemy ships will be hostile at the start of the encounter.
Without a letter of marque, you should not be allowed to capture enemy ships. That's piracy. The whole reason for getting a letter of marque is to legally be able to take prizes - in reality, the East India Company got letters of marque for its ships for precisely that reason.
Advantages:
- You will get special weapons at promotion and maybe 1 special ship on a very high rank.
- You can sink ships from nations without theire relation getting worse cause you have the nation relation
Provided, that is, that you only have one letter of marque, and are therefore tied to your nation's relations, so enemy nations are already hostile. If that nation makes peace with yours then your relations become neutral. If you have multiple letters of marque then you're independent and that nation remains hostile to you.
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- You wont have to pay mooring costs in the ports of nations you serve
- You can use the room in the tavern for free in the ports of nations you serve
I don't see why. You're not a commissioned officer so the Navy won't pick up your bills.
- You can use the diplomat for everyone (if you have more then one LoM).
Disadvantages:
- The gouvenor will require you to pay a sum of money each X months to keep the letter of marque
Why? Your initial sum is to prove your commitment. After that, what the governor gets is a share of your prize money. In reality, privateers (and commissioned officers) wouldn't sell prize ships themselves. The prize would be handed to an admiralty court for disposal, then the privateer (or naval officer) would get a share of the profit. In game, unless someone fancies writing a whole new set of code for the admiralty court, this is effectively handled by the fact that you don't get anything like full value for a ship when you sell it - the difference is what the governor takes as his share.
Advantages:
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- You get a discount at buying gunpowder etc in the pirate store.
Disadvantages:
- Everyone is your enemy at the start
- Your crew will demand to sign articles very soon
- At the start selling at the pirate store wont give you much, but when your rank increases this will become better.
At the start, selling anything anywhere in any playstyle doesn't give you much because your Commerce skill is low and you don't have any of the Commerce perks. After you've done enough trading to raise your Commerce skill and gone up enough levels to raise your Commerce perks (or preferably hired a decent quartermaster so you can put your Ability points into other perks), this will become better. There's no need to penalise a fledgeling pirate even further. Or to exaggerate further the boost that he gets later in the game. And why would the pirate store give anyone a discount?