I get a kick out of some of the quests in the game, and they're definitely a bit better than they used to be. Granted, plenty of them are still "Kill 8 boars," or "Gather five boxes," but there are others these days, especially into Outland and beyond, that have a bit more depth to them. And I enjoy unlocking new skills and shaping my character to be my own.
I enjoy taking on the instanced dungeons in the early, from Wailing Caverns to Shadowfang Keep to the Scarlet Monastery. And it's a fair bet that once I get to some of the later ones, I'll enjoy them as well. I also like how some of them have changed; SFK is much more interesting with the Worgen layer on top.
I like the organic economy that ebbs and flows in the game, and I like finding ways to exploit it to generate funds, which I happily use to further exploit market inequalities, or to buy things I want like gear or recipes.
I like collecting resources, and sharing them between my characters to really craft the shit out of the game. I haven't managed to get multiple characters to high enough levels to make a huge difference, but I've definitely put together armor, weapons, and potions for my guys to share.
So now that I've got a full-time job, what's been stopping me? Well, the thing about me, and it's different about me versus a lot of other users, but...
...I love the grind.
I feel like it's the grind that makes you feel like part of the world. The quests may not be amazingly crafted as far as lore, but they add little pieces of what's going on in the zone to your experience. Lots of stuff like this helps to explain why you might want to delve into a particular dungeon, like the quilboars being general assholes in the south Barrens, and how conquering RFK and RFD are your ways to strike back.
The grind also makes me feel like I own my character a little bit more. You used to have only certain weapon proficiencies when you started your character, based on your class and race. If you wanted to learn how to use other weapons that your class could use, you had to seek out weapons trainers and pay them a fair sum in order to learn how to use that weapon type. And you leveled up your use of that weapon just like any other skill, so your first few swings with a new weapon would be ineffective.
Was that "fun" for most people? Probably not. But it added a reason to search around the various capital cities, which made you learn more about them, which made you feel like more a part of the world you were living in. Now, you know all proficiencies just by creating a character. You also don't need an actual "fishing pole" to go fishing; once you've got the skill, you apparently have a phantom fishing pole that sprouts as needed. Which I guess whatever, but I liked that you had to commit a backpack slot to a fishing pole if you wanted to fish. Again, character choices.
In the end, because of the aspects I mentioned above that I enjoy, I'll probably still get back into the game (if I haven't already by the time this gets posted). But I think when people complain about the grind, it'd be important to remind them that the grind is there for a reason. When people complain about having to carry a mining pick around to mine ore, remember, it's there for a reason.
Immersion is a tough thing to achieve; I don't think we should so easily dismiss it.