In my experience, most pirates "spam" the sword simply because they are too lazy to take the time to learn about the mechanics associated with the sword. They seem to think that attack, block, and charge are all it's capable of. If that's you, then you're wrong.
You can do a combo attack up to 3 hits, which by itself gives you some strategy with cancelling and faking out your opponent.
You can do an advanced sword lunge that allows you to have more movement during the hold of the charge, as well as a jump at the release of the charge that gives you both increased height and distance to better attack your foes.
There's a sword dodge that can be used to get closer or further away from your enemies, or simply cause them to miss. A lot of pirates don't even realize that this defensive manuever can allow you to pass through them, giving you a chance to escape if cornered, and or stab them in the back.
There's a running sword slash that virtually nobody knows about unless I inform them of it that, like the sword dodge, can be used to get closer or further away from your foes. However, it's offensive in nature and allows you to extend the reach and arc of your sword swing with a minor speed boost as you engage with your attack or retreat with it. Furthermore, it's great for circling around your nemesis' block.
Then, of course, there's the cancel - the ability to switch to something else mid-swing - like your gun. It's very useful if your opponent is blocking; you can cancel after the 2nd swing and shoot your confused adversary in the face when he was expecting you to bounce off with your 3rd strike.
Pirates have to go in with a plan, be mindful of their opponent's attacks or mannerisms, and be quick to counter. Sadly, most are content to swing away mindlessly in the hopes of getting lucky while charging directly into their antagonist's direct line of fire (you might as well blindfold yourself and hire a firing squad). Even sadder are their gun-toting rivals who fail at learning how to move or get out of the way when there are so many stupidly simple ways to do so...
The sword is perfectly balanced as is; the community just needs to be educated better in how to use it.
Other issues, like with hit reg, are exactly that - other issues. Those issues, while needing to be addressed, are not sword issues like some seem to think. So if you're 1 of those pirates, get that out of your head right now; nerfing the sword will not fix hit registration issues.