It has been a long, long time since Deathwing took a deep breath and blasted apart Stormwind's Park. If you're a newer (meaning post 2010) player, you might not realize that rather than a burning, smoking crater that dips into the ocean, the area north of the Mage District and west of the Cathedral Ward in Stormwind used to be its own area.
The Park wouldn't look all that impressive compared to the graphics of today, but it was, essentially, the Night Elf part of Stormwind, where Druid and Hunter trainers could be found (there was another Hunter trailer in the Dwarven District as well, but none in Old Town.)
Well, 7.0 will see Stormwind's construction workers finally get off their behinds (hopefully well-paid this time) and repair that gaping maw of destruction, which will prominently feature a [REDACTED.]
Additionally, and more ephemerally, it looks like Legion will have its own sort of variant on the famous/infamous Zombie Plague from the pre-Wrath event. It appears that going through major cities, players will sometimes encounter "Dark Whispers" with promises of power. This will give you a buff that slowly corrupts you with demonic magic and allows you to spread it to other players, eventually transforming you into a Dreadlord (hostile to the rest of the world.)
It appears that this buff can be clicked-off, so you can opt out, but I'm curious to see if some of the other features of the Zombie Plague make a comeback, such as a gradual ramp-up of sources and virulence, or the ability to team up with members of the other faction.
In addition, there seems to be a pre-launch quest line that involves dealing with cultists who are already taking the "if you can't beat them, join them" attitude toward the Burning Legion.
So it sounds like for the first time since Cataclysm, we might be getting a full-fledged launch event.