I've heard that instead of gemming stamina you can gem +defense rating, for the dodge and parry. Right now i am 15 above the defense cap, because of a trinket, should i take out my defense rating gem and gem more stamina or just stay with +defense?
Also, as a DK, you'll be swimming in Parry rating from Strength already, which means that the Defense will give you less Dodge+Parry than a Dodge gem will.
With the current endgame content in mind, I'ld say the only gems you'ld ever want are Stamina, Hit/Stamina & Expertise/Stamina, with the last 2 only ever useful for getting socket bonuses that are stamina
(And ofc only if you're not capped on hit already)