Flameshock and Reverberation are your friends. Elemental Weapons are not. When you are 5 seconds away from releasing the empowered Earthshock, cast a Flameshock then your Earthshock will be 20% bigger. Add Lava Flows talent and you will be throwing more lightning during the Flameshock. Change the Elemental Weapons enchants to "Shock and Swarm"
Add in the Insect Swarm, Improved Insect Swarm talents for more nature damage. You can also add in Earth and Moon, Furor and Master Shapeshifter from the druid talent trees for even more Nature damage. Change out some enchants for Improved Insect Swarm enchants for even more nature damage.
Remove Storm, Earth and Fire talents and Sunfire Enchant for Lightning Strikes Twice. Add a single Endless Lightning enchant, this is less damage but more lightning touches and will get you to the big Earthshock faster while clearing trash in dungeons.
Swap Lightning Shield for Water Shield, you should not be being hit.