Tell me, what was well done in Silverpine, for example? First thing which annoyed as hell was the travel distance between quest hubs. But okay, you say exploration and adventure. I could agree.
The problem is that Silverpine had NO interesting story and NO interesting landscape whatsoever. Back in vanilla I ever felt to quest there just because I had to do all this running because... there are gnolls on an island? A mage is sitting on his arse in a castle and no one cares about him? The werewolf storyline was a bit better - a bit. And about exploration... It was probably the most mundane and boring place ever in WoW. I mean, the big wall was quite awesome, but thats it. Most of the storyline took place in shady forest, then more shady forest, then, hmm, a farm in shady forest and maybe a small village in shady forest.
Thats what Cata improved. Places like Thousand Needles or Silverpine forest, that were more annoying then challenging or interesting. What could you say about quest likes in old TN? There were some centaurs, Grimtotem on cliffs that didn't really bother you, and elite cat quest. And of course, the infamous Mirage Flats, where every new player in WoW thought about incredible racing quests, and got "farm this, farm that, we kinda need it I guess". Now there are GREAT storylines there. Maybe it's too "guiding by a hand", but at least you can say what you did there. Quest to free Magatha? Awesome as fuck. Quest to kill and then ressurect an awesome pirate troll? Great as well. Having your private ship? Tell me which part of those things don't you like.