If you're playing dps ele you probably want to take a staff and be on the lightning team since you can do great dps from range. If necessary you can throw an air 3 at the seekers to get them away from you or earth 4 to stop them from creeping towards you in the first place. Controlling seekers and not letting them roll around wherever they want is really important, they will kill you and the rest of your team if you let them sit on you for more than a tick or two.
I'm not sure how much of the fight you've seen, but as the fight progresses it gets more complicated and positioning becomes really important. Sections of the arena will start lighting up and doing significant damage to anyone standing on it, and you have to keep him moving out of the lit up sections so he doesn't spawn green in them. CCing him also becomes important, he will stand still and channel a thing and you have to break it to make him stop it. It's important to do this so you can keep moving. I don't really play ele much for VG but I imagine air 3 would be useful for that.
This all sounds horrendously boring, I don't want to grind, I want to be told a story. Anet pls.