To mods: this video shows a parkour event from a closed private server, I'm not here to talk about it, since it's closed and no longer in service. I'm using the video as example about a possible feature to implement in the real WoW.
Dunno what do you think about it, but adding these kind of dangerous races would be very cute and lovely.
The example in the video is clearly aesthetically bad and would ruin the map. But I think some places in Draenor are good for something like that. Azeroth even more!
There are places in Azeroth that are forgotten since years, like Deadwind Pass.
In Northrend Storm Peaks would be amazing (but too sacred to touch i think), aswell as any other area of WoW with pikes and drops!
This already exists in Guild Wars 2, they're called Vistas. I hate them. They're fun the first couple of times and then they get really old really fast.