So, as most of us know, guns have been somewhat superior to swords for a while now, even with the recent damage buffs. I don't think buffing the sword damage is the way to go though. I think a new gameplay mechanic should be added, a new item that takes up the weapon slot, the Shield. The function of the shield is, it's not for attacking, but for defense exclusively, as it would be similar to the sword in that you hold right click to block, yet have no attacking functionality. However, unlike the sword, it should block bullets coming from the front. This would add a new rock paper scissors dynamic to weapon loadouts, no longer could you double gun mindlessly, you would have to time your shots to when the player has their shield lowered, or get behind them. Now, optionally, the shield could not block sword attacks at all, although that may lead to swords being overpowered, so maybe it blocks bullets and basic sword attacks, but doesn't block sword lunges. It should also slow you down a lot when blocking, like blocking with a sword but probably more, and also not have the hop/dash function of sword blocking. It could have a weak shield bash attack doing 10 damage, but that runs the risk of it replacing swords so it's probably best for it to have no attack.
I think this would balance out snipers and pistols, and also mindless blunderblussing at point blank, as there would become a new mindgame about when you shoot, and when they lower the shield, as if they keep it up fprever you'll just jump behibd them and attack their back, or sword lunge them, or throw a blunderbomb behind them so it hits their back. When i say shield I'm imagining a small shield held in one hand, somewhat like the shields used in Breath of the Wild, but they could be bigger. There is also huge potential for lots of creative skins and designs for a shield, made of wood, metal, painted, decorated, etc.
They also fit the time and era and look of the game, as metal soldier armour is shown in the stonewall clothing set, so small shields would fit and also could be used by real life pirates who love to play dirty and use whatever tricks they can in combat. The sailor one could be something cheap like a wooden soup pot lid or something. The shield would also stop you being helpless if you are in open water combat or open island combat with someone when you have no sniper or pistol or no ammo. It would also give solo players more of a chance against large crews, as often those fights just end up being a firing squad of a whole galleon shooting snipers all at once, this would give that some counterplay. I think this would add a lot to the game in gameplay depth and emergent behaviour, and make players think smarter before shooting.
Grappling hook:
I think this would also be another much needed feature. I'm not sure if it should take up a weapon slot for the same of keeping it balanced or not. It may be too strong if it was a regular tool that everyone could use as soon as they spawn in and instantly. Perhaps it could be an item like the blunderbomb that must be found in the world. It could probably work quite well if they took up slots in the throwables section, meaning if you want to bring grappling hooks when boarding a ship you need to sacrifice carrying some blunderbombs or firebombs. The purpose of grappling hooks, is because in my opinion and many others', boarding ships is completely unbalanced, i know the blunderbomb was added to counteract this, but in my opinion it barely helps at all. If the enemy crew is camping the ladders, there's no way you're getting on board alive. They can camp it with blunderbusses and one shot you before you can even act since you haven't left the ladder yet. And on a galleon it has only 2 ladders yet 4 players so they can have 2 players guarding and the other 2 doing whatever they want. This also leads into galleons being overpowered in pvp vs other ship types. Galleons will likely always have the advantage due to higher numbers of players, but they can still be made more fair and balanced. The grappling hook would let you throw the hook in an arc, like the blunderbomb, and the rope trailing behind can be just visual like the harpoon rope, and basically once the harpoon lands on a surface it sticks in with its hooks, and then functions somewhat as anladder or reverse harpoon, with the player being able to let go of it with left click or F, and reel themselves in with either forward or right click, and to lower themselves back down by pressing back. This would be lead to an emergent property where, the bigger the ship, the more places to guard for players climbing up the sides with harpoons, making the amount of guarding from boarders scale with the number of players on the ship, nerfing galleons and buffing smaller ships.
Grappling hooks are also a total staple of real life pirates, as they would throw them at other ships to pull them in and/or to climb across the rope for boarding. It would also feel sooo epic and cool to have your ship close but not close enough to grab a ladder, and to throw a grappling hook at the side of the enemy ship, and swing or climb across, it would add so much to the epic pirate simulator experience. It would also stop those annoying moments where you try to board an enemy ship, come within a hair's distance of their ladder but just miss it, and have to watch as they very slowly gain distance from you as you swim after them.
Since they let you hook to any surface they would also let ypu make awesome high skill plays like grapple hooking the enemy sails beam or mast and climbing up for a sneak attack. Now, another optional addition is letting them grapple hook to surfaces on islands, which would let you climb steep cliffs and such and reach areas you'd previously need a cannon to reach, although i understand if the devs wouldn't want this part.
Now, one last idea which is maybe a bit more far fetched: metal planks. They would basically be wooden planks but better, yet a limired rare resource, like how mangoes or pineaples are better food but rare. They could be for when taking heavy fire from the enemy, or just fortifying vulnerable areas on your ship ahead of combat. They wpuld look like wooden planks with metal plates/strips wrapped around or nailed onto them.
When you use one to fill for instance a hole on your ship, that hole is basically twice as protected now from cannon shots, if someone shoots that hole once with a cannon, first the metal on the plank will be blown off, leaving a regular wood plank on the hole. If they shoot it again, it would blow off the wood plank, just like normal, making a hole in the hull. These metal planks would also be better used on the destructible parts of the ship, the masts, wheel and capstan, making them more fortified.
A chainshot does 3 damage to those ship parts, which cpuld be kept the same if you consider a wooden plank as having 1 health and a metal plank as having 2 health, so shooting a normal mast with a chain shot takes 1 hit to down it, and if that mast is covered fully in metal planks then it would take 2 shots with a chainshot to take it down. As a side note i also think rowboats should be repairable from their damaged state using some wooden planks.
Metal planks could be made so they can only be added to damaged areas, like wooden planks or they cpuld be made so they can also be added to undamaged/fixed areas, on top of the wood plank, making it cost 1 wood plank and 1 metal plank to repair and then fortify a ship part. They could also be made so to fortify a undamaged ship part ypu have to first place a wooden plank and then apply metal plating to it, increasing the time needed to fortify your ship, balancing this powerful mechanic. It may be better for them to need to be used on a damaged area though, rewarding players for surviving combat, and stopping situations where a galleon dominates a server sailing around in a completely metal plated ship, as they can only metal plate some parts of it that are damaged by combat.
Sorry for the long post, and thank you for taking the time to read this! I think these features would add a lot of depth to the game, and hopefully not be too hard to program in.
