I find Nagrand one of the prettiest zones in World of Warcraft. It combines a green lush environment with fantasy elements like floating rock islands and waterfalls. The points taken over by demons and having been corrupted make a really interesting sharp contrast, giving motivation to fight the corruption (not that this really would be possible). But right now I'm doing quests with my level 66 mage in Nagrand, and I must say from the quest design point of view, Nagrand isn't perfect. There are far too many "kill 30 talbuk, 30 windroc, and 30 clefthoof" quests, and once you did the first series, you're told to kill another 30 of each of slightly higher level. So you basically go somewhere and kill everything that moves for an hour, which isn't all that interesting or different from grinding.
The most interesting quest in Nagrand is probably the one with the trampoline. You spend more time trying to figure out how the trampoline works than killing stuff. I had some problems with the summoned bird being bugged and evading me, but a friendly shaman helped on the second try. The background story of the weak Mag'har leader is also interesting, leading to a visit of Thrall to his grandmother. But there are many, many quests that are just about killing X of this and Y of that. A bit more interaction with the environment or background story would have been welcome.