Well, lore-wise, there wasn't much for a rpg setting with variety until now after the forces of Order had once again established cities in the mortal realms. Before that it would've been a chaos/undead city with minimum background appeal or set in Azyrheim without any real reason to defend a city with a OP defense force(I.e. Sigmar).
Everything else at that point was ruins and fallen civilizations like the fallen Lantic empire that turned into the Flesh-Eater court or the abandoned floating isle fortresses of the Swifthawk Agents to name but a few.
Hammerhal is a mix of getting to see the setting grow and a reward for safeguarding it and the other two cities during the summer campaign. Funny to think we'd be in another city (or none at all) if the results turned out different.
As for why we'd get evil elves first, it's looking to tie-in tightly with the Slaanesh sub-plot and it's release.
-Numerous Slaanesh short-stories and side stories have pointed them out as having deduced their master is being held by Malerion (Malekith).
-Tzeentch was responsible for it's imprisonment in the first place while using it as a distraction to cripple Sigmar's pantheon. Recent lore shows Tzeentch's forces acting randomly but actually being used in a arcane plot that many suspect to cause even more turmoil in Order's domains. (Likely the release of Slaanesh at the heart of the Aelven forces)
Hammerhal even plays more on this:
Lord Redomir is a Chaos Sorcerer Lord of Slaanesh.
He is the mastermind behind the Chaos attack.
Now that's really good.
I hope this means that at least we'll know something about Slaanesh later this year.
Awesome where did this wonderful nugget of information come from?
edit: Right just checked the warhammer community site.
https://www.warhammer-community.com/2017/02/21/closer-look-the-villains/
Finally, we have Lord Redomir, a Chaos Sorcerer Lord of Slaanesh.
Long has he, and sorcerers like him, attempted to draw the attention of their lost Chaos God, but to no avail. Now he thinks he may have found a way to locate and awaken his gorged and sleeping deity. Gathering to him followers of Chaos and binding them with promises of bloodshed, mayhem and desolation, he has forged an alliance and seeks to fulfil his destiny…
So the Shadowkin are looking to be the opposing force against whatever a released Slaanesh brings to the table.
Anyway, I'd like more good elf focus as well. Since Tyrion is the god of light whose followers, like the Order Draconis, are Aelven knight orders and he had human worshippers as well, I'm hoping the realm of light will reveal a mixed knight faction that'll please both elven and Bretonnian players.