I have a confession to make: I haven't been playing a lot of WoW in the past couple of days; instead I've been playing Dragon Age. This is unusal for me in so far as I never played a single-player roleplaying game before. Yep, you read that right. Before I got into WoW I used to play old school adventure games, real-time strategy games and The Sims, but never any RPGs. They looked very similar to action adventures to me, and I didn't like action adventures because they took the old school adventure games that I loved and slowly shifted their focus towards jumping, running and fighting, which was simply not something I wanted from the genre. The only reason I ended up getting Dragon Age was because Spinks raved about it when it first came out and I was intrigued by the things she posted.
After I finished playing with the extremely detailed character creator, I found that the game itself looked pleasantly familiar to a WoW player: I need to upgrade my gear, clicking on things that sparkle is useful, there's my health and my mana bar, warriors are the tough guys in plate, mages cast cone of cold and heal... wait, what? Healing mages? Well, since there are no priests or anything of the like, someone had to do it I guess.
The main difference between Dragon Age, or any single-player RPG I suppose, and a game like WoW is the shift of focus. A single-player game is all about the story: You need to go out and save the world, and everything you do is focused on making the next step necessary to achieve that goal. You gain levels on the way, upgrade your gear, learn some professions... but it all feels damn trivial in comparison. I mean, my main character is a herbalist and can make healing potions out of flowers she finds by the road, but considering the same potions drop off dead monsters like candy it feels pretty superfluous. Not to mention that there are no skill-ups for using your profession or anything like that.
Upgrading your gear is nice, but there don't seem to be all that many different options and it all kind of looks the same (boo realism). In WoW I get excited about gear upgrades; in Dragon Age the constant need to check whether what just dropped is better than what I already have before selling it all simply feels like a nuisance that stalls my story progression - though I guess the fact that I'm having to manage the outfits of a whole party at once isn't helping. (Are these boots an upgrade for my warrior? No? What about the other warrior?)
In contrast to that, a game like WoW has an overarching story too (like in the case of the current expansion the expedition to Northrend and battling the Lich King), but it's comparatively low-key. Most quests are only very tangentially related to the plot (at best), and a lot of things that are basically just "fluff" in single-player games are inflated to be full-blown, very time-consuming features that become a goal onto themselves, like gaining levels to be able to advance, skilling up professions or collecting all the best gear available.
Looking at it from that angle, I think I can understand why many people complain about a lot of aspects of WoW being too "grindy", if these people are used to the way these things work in single-player RPGs. Why do I have to waste so much time collecting all that gear if all I want to do is kill the Lich King?
Coming at it from the other end of the spectrum however, as someone who started with MMOs without ever having tried anything similar, it feels like the MMO way of requiring everything to take a lot of time is the normal way to go and anything else is lacking. After all, things like skilling up professions can be a mini-game of their own! It's all about perspective I guess.