you said that twice :P
but yeah i agree, upgradable cannons in the future, and it makes more sense to have a triple barrel like the dutchman, or at least a way of upgrading broadsides to triple barreled, i sure would use them more

since they are the stationary heavy guns, and the crew usable guns are more like typical swivel guns in pirate lore, much lighter and supposedly used mainly to clear the decks with grape shot before boarding.
what id like to see is different guns,
like a blunderbuss (sort of a shotgun type musket)
and the standard musket of course

cuz while i like the pistol..id like to see some variation in the different guns, same as the swords
like a rapier/smallsword, quick, finesse, thrusting techniques
a sabre
broadsword, slow but heavy hitting, as they were supposedly used by pirates but not as popular as a cutlass because of their weight and length.
i like what someone mentioned a few pages ago too, about an ax, as boarding axes were popular weapons during that time, used as to cut ropes to disable sails and to defend or attack against boarders/boardees mostly.
anyways theres tons of good reading at the library or online...very fascinating

and interesting learning about all sort of weapons they used back then. molten iron filled cannonballs, iron bars lashed together with rope fired out of cannons that when they struck objects, they fell apart, skewering wood and unlucky crew..yikes...who said games dont make u learn anything..