On my first pirate, I mastered sword first, and got round to all the other weapons later. She mastered all skills (including fishing and potions) before level 50. So that works as long as after you master sword, only use it in a dire emergency. Unless, of course, you don't mind mastering with not all skills mastered.
With my second pirate, I'm taking it a different way. All land weapons will be leveled equally, and sailing, cannon, potions and fishing are going to be done when I feel like it. All of her land weapons are at a level average of 16, and my character is level 28.
You don't have to use weapons you don't like at all, I guess at the end of the day it's all about showing off to other players how much you've done. I've seen loads of players who have mastered while barely touching certain weapons, like grenade (grenade is a widely hated weapon).
Sword is definitely useful in most situations, but each weapon is useful for something different. For example, it might not be best to use a melee weapon on an enemy with a ranged weapon, because they'll keep backing away and you have to chase them.
Just level what you like, and decide whether you want to use a different weapon once that's mastered. There are so many ways of leveling pirates - and the way you like the most is always the best way!
(post 900!
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