What does that mean? Absolutely nothing.
Whether we're talking about WoW or Guild Wars, the dragon made from a mish mash of solids and glowy non-solids is in fact.. nothing new. It wasn't new when Arena.net did it. It wasn't new when Blizzard did it. Neither of them copies one another, and any similarities are pure happenstance because they both just happen to be Dragon creatures made up of a mish-mash of solids and glowy non-solids.
I'd actually be able to conjure the energy to care if the fights were identical, but we've seen the fight with the Shatterer in Demos, and the two are nothing alike where it counts.