It was pretty good but... it's a pity they never truly finished it.
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Cataclysm contained the best quest zones in the game. The revamped zones are top notch for the most part. The endgame zones were pretty solid as well. In fact I remember bowling down leper gnomes in Uldum and thinking to myself "this is my favourite quest zone of all time". Not kidding.
Also, serious nostalgia goggles re: linearity of quests. WoW was always linear, in the old days quests just didn't link or flow at all, and there were huge gaps in zones with no quests (eg, all of Azshara). This criticism is ass-backwards. They actually made questing WORK and people complained about it. Vanilla questing was horrendous. And since when has there been anything between heroic and raid? Until MoP...
It's like you don't remember how all through late Wrath these forums were wall to wall bitching about how easy Heroics were. Then they go and make them difficult again and what happens? Exact same amount of bitching, only now about how they're too hard.