I would love it if instance existed in open world where you can see others killing a dragon out in the open but not closed off world(of coursei understand it would be claimed by only the alliance that initiated). Competition is another thing i would like as well as an absolute open world content.
They're still going to have instanced dungeons, but they're not going to make absolutely everything instanced... but their not going to make absolutely everything openworld either. They're going to have both. They're going to increase instances where you CAN see others, like zones, so that they can add more unique areas. You'll still see others and what others are doing.

It's a wise use of instances to maximize the game's potentials.