Changing zones can sometimes be interesting! I first came to think about the environmental changes while flying on a gryphon in TBC, passing through Dun Morogh > Searing Gorge > Burning Steppes > Elwynn Forest.
Made for the Swedish magazine "Level presenterar World of Warcraft" (Level presents World of Warcraft) no. 2/2012.
Lol. More blending between zones would certainly be appropriate. It's gotta be all those geologically-impossible-to-explain-sheer-dropoff mountain ranges messing with the laws of environmental physics. XD