Your gear looks fine, and those are very solid avoidance/mitigation stats. If you're looking to MT for 25 mans, you could definitely raise your hp pool and the Gossamer Essence is a good choice. I'd suggest dropping the valor medal instead of Repelling Charge. Additional defence will raise all your avoidance/migitations ratings across the board while valor medal will only boost your dodge.
This is an old debate what is more important Avoidance or HP pull. You have 53% avoidance which is really solid number. But eventually the MT will be the one with 50% avoidance but 31k HP... I love High avoidance but low HP is never good.