I'm definitely an explorer gamer myself, and I've been enjoying the journey in WoW way too much to rush to the end. As a matter of fact -as you can read from my former posts- I'm a bit frustrated over the fact that people are rushing to the famed End Game to grind the same mobs night after night. Then again, the levelling game gets stale after the second or third levelled toon, as the mid-game content is stable and not evolving at the same rate as the end game content.
As it happens, Crucifer commented my "Too easily soloable?"-post nicely. To put it short, Azeroth is a timesink up to level cap, each expansion measured in 10 days cycles: in full month of played even the slowest gamer would reach the cap and start grinding raid instances. On the other hand, raid instances are available from lv 60 onwards, but no-one is taking the challenge at that point: instead, it's more "efficient" to rush through the solo content to the level cap, avoiding grouping on the way. There are only few instances that you really want to visit on your way up there.
Azeroth is full of lame quests, too few long and involving quest chains and the continuity of the "chapters" -or storytelling quests- is non-existing. For example, I wanted to get into a chain which would have lead me from starting areas to Eastern Plaguelands, suitable for my alliance priest. Not available, only bits and pieces you really have to seek to find the route there. And the speeded overlevelling takes the challenge off of this endeavour. On my horde toon I tried to find continuity in the Silithid-storyline, but that too is split into incontinuing series of quests, which you really have to seek to make any sense of it. The lore is not used to the max in here.
Like Crucifer said in his comment: the game isn't episodic, it's not growing the continuity or the epic stories started from the newborn hero-in-training.
But as WoW isn't great in storytelling, it's lacking in the social aspects, it's not a sandbox to do as you please and it's unchallenging as a game, what is it except a platform for the raiding population to bang their pixels against 'the only challenge in the game'?
I think it's eye candy entertainment: panem et circensis for the people.
What if, this is just speculation, someone in Blizzard got to her/his head that to make their cash cow timesink even more so by changing the original quests into chains leading the character from heroic deed to another, providing speedy and interesting levelling experience? Some might say that this is more railroading, but then again, if the levelling told you a story, wouldn't you be interested to read it through at least once? And as Azeroth has such a huge amount of those bits and pieces to connect with a message from a NPC or a connecting quest from another, the levelling experience would be easily different each time.
The other thing completely is the fact that WoW isn't sandbox enough, as it has already railroaded the way people play the game: from mob to another, quest to the next and from area to area to get the exp needed to level. It's not open enough to make the game interesting anymore.
The platform for great storytelling is there: the World of Warcraft -Azeroth- is beautiful, intriquing and involving place filled with lame excuses for quests and utterly stupid pixel mobs. How hard would it be to change it bit by bit in the next content patches? I mean, EQ and EQ2 do it constantly with less fuzz.
Blizzard, its time to wake up.