Originally Posted by
shadowboy
Thing is, expertise cap isn't achieved at the expense of mastery, it's generally at the expense of haste, crit, and hit (if overcapped) and expertise is better than those. The only way you're losing out of expertise to gain mastery is if you have very little mastery already present on your gear--in which case it's a gearing choice (or rng non-choice if your case is similar to my search for daggers), meaning you need to reforge into mastery. You should choose gear that is more expertise, or better yet, more mastery heavy.