I enjoy WoW lore immensely. Enough so that I bought a few of the novels.

Swotor has som really good stories

Bump

it depends on the mmo. some have good story, some dont.

i have played wow, rift, swtor and warhammer (played other games but i spent most time with those) most MMOs that i have played atleast make an effort to motivate the player and explain why certain things are, like pvp or classes. also they have a personal story arc and/or class story arc and an overall/faction story arc of missions. why is PVP for example? most MMOs contextualize PVP in some way (usually through rival races/factions). in destiny there is PVP because fuk u we made halo. why does all races AND classes share the same starting area in destiny? because fuk u. personal story: you woke up on earth then went to the moon, then venus, then mars, then you won ... i think. class story: nope race story: nope overall story: nope the first time you meet the speaker and the final speech cutscene could very well take place on the same day in the story, who knows? the story just isnt there.

It definitely varies. I am one of those guys who loves implied story, which is what we have with Destiny. A lot of the background is tied up in the grimoire and if you just run through the main storyline it leaves much to be desired. The Secret World does this sort of thing really well with a meaty main plot, interesting characters and a grimoire-style lore system that expands on the story you play through, and gives background information in the form of short stories, and slightly crazy rants. On the other end of the spectrum Final Fantasy XI (the first FF mmo) has a plot that can be summed up as "You are an adventurer, go kill things." at least way back when I was playing it. No story there but what you make on your own through gameplay. Now if its character development you are looking for in your story: Pretty sure no MMO has done that, at least not of your own character. I can't imagine that'd be easy to pull off, after all you can make your own goals to a certain point, and when your motivations don't coincide with what your character says their motivations are it can make for that weird dissonance where your character is all "This is serious business, millions of lives depend on me!" and you are just flipping cars for kicks minutes later. MAYBE Star Wars: The Old Republic pulled it off, but I stopped playing at one point and I couldn't get back into it to find out.