FATE will be the ONLY open world content?

Define "content".

Quests would still be open world and instanced. Are quests content?

Levequest are open world, are they content?

Guildhest (replacing Behest) shown to be open world as well, are they content?

I think what they meant by content, is the raiding-like content, and there won't be any raiding-like in open world with the closest to it being FATE.