What are your "favorite" (most immersive) zones in WoW? Disregarding quest efficiency or annoyance.
Classic: Eastern Plaguelands
This zone was intimidating because it was the end game of the end game. EPL was greatly populated with threatening undead and roaming elites ready to end your life. Floating above was the doom fortress, Naxxramas.
TBC: Netherstorm
This is where the devastation of Outland really struck me. The chaotic floating rocks, severe thunder storms, and ambient music sucked me right in. Even outskirt "islands" crawling with ghosts of the past added to the apocalyptic mood.
WOTLK: The Storm Peaks
I really only need to mention two things about this zone that attract me; the music and the battlefield of giants forever frozen in time near the sons of hodir quest hub.
Cataclysm: Vashj'ir
Vashj'ir is almost entirely why I mentioned to exclude gameplay aspects from this list as the 3D disorientation is very much a reality. With that aside, however, I totally felt like I was 10,000 leagues under the sea within this landscape. The underwater caves sealed the deal.
MOP: The Jade Forest
Hozen, Jinyu, and Tigers oh my! There's only so many ways you can design a forest level over and over but this zone definitely feels like its own entity. The lush color scheme along with the jade-oriented operations going on here (statue, mine) add to the theme overall. Also love the music.