Voted Shadowgeln.
For traversal its Shadowglen, between the tall tower and the more spread out mini zone it always feels like it takes way longer then it should to complete. honorable mention here goes to Kezan.
For aesthetic, I find the Valley of Trials to be really boring to look at. Deathknell gets #2 here.
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This being a ranking of the mini zones we spend the first 4-6 levels in, I feel his point somewhat stands.