So with 2.3 removing the Weapon Skill rating, Expertise was added back in it’s place. Originally with this change Orcs and Humans had their racial changed from Weapon Skill increases with an added 1% crit. This was effectively a nerf for tanks who used those racials.
Fortunately, the latest 2.3 patch has changed the 1% crit to 5 Expertise while wielding the required weapons. What does this mean? Well, it reduces the chance to be dodged or parried by 1.25%. For tanks who can take advantage of the necessary weapon, this will translate into more hits, meaning more threat and more rage.