In the last major update, it was stated that now, all Privateers use WILL, instead of being STRENGTH or WILL. That being said, all pirate's weapons give a boost to their class's main stat (I.E. Agility for Stabby, Strenght for Smashy, and Will for Staffy), but now since privateer's use will, wouldn't that mean that they're Slashy/Smashy weapons (that the game gives by default) should also be will based and not strenght based? Other wise, Privateers would start needing to use Sfaffy weapons to add an extra oomph to their attacks.
The equipped weapon actually determines what attribute (strength, will, or agility) is used for the attack. Some combo weapons (smashy/slashy, stabby/smashy, etc.) could actually use two attributes for the attack.