A lot of graphical improvements have happened for World of Warcraft over the years, but the game is still using the same fundamental graphical engine it was using with launch. That is not surprising; those things are hard to overhaul. So this video of Duskwood recreated in the Unreal Engine 4 should be taken for what it is as a look at a wholly different set of rendering rules, something offering a different look at the same basic structure of the in-game area.
The video makes particular use of the engine’s lighting features to keep the zone cloaked in more shadows than its in-game counterpart, and it’s an interesting look at an alternative to WoW‘s graphics. The author is quick to point out that this is entirely a fan project, not a comment on the game’s graphics or the age of same.