Add Ishgard as a nation to join.

[Gilraen]

We're at the end of the story from the base expansion itself, not the subsequent patches that add more story.

Exactly, we're nowhere near the end of the Story. The three nations were enjoying relative peace when the adventurers started filtering in. Ishgard is far from peaceful, it simply doesn't have the resources to see to the well being of adventurers much less it's own citizenry. Again, we likely won't see Ishgard as a starting city until it's own story is resolved and it's enjoying enough relative peace to reasonably host adventurers. I honestly think we'll see Revenant's Toll become a starting city long before Ishgard ever does.