Inevitably, Blizzard ends up surrendering a degree of control to players who think they own the game world (they certainly rent it), or facing a backlash when they don't. "It's hard to not let that sometimes steer you in a way: well, I guess my instinct as an artist is that we go left, but the community sure seems to want this idea to go right. And that's a very strange space to be in," Metzen says.
"Sometimes you go right for the community, and sometimes you draw a line in the sand and go, f**k it, we're going left. You just have to hope that people stick with you, even through patches of content that they're not entirely thrilled with." And the feedback can be brutal. "The smaller per cent of truly vocal fans on the internet that just rip everything you do to pieces... Sometimes it hurts, and you're left to conclude, like any artist in any medium, boy, I guess they really didn't get it."
Happily, WOW's fiction works with its design; it's a social game, and Warcraft's concerns are societal and political. Metzen calls it "a study - clumsy or not - a study of societal breakdown and why do we keep clobbering each other, why does hatred persist generationally?" (Metzen describes Blizzard's fiction as "clumsy" more than once; he's being modest, but perhaps also aware that their populist creations deal in broad brushstrokes.)
Nonetheless, he admits that, after years of working primarily on WOW, he was "desperate for" the personal focus and writerly freedom offered by StarCraft's linear narrative.
"WOW is so macro," he says. "One race can't really lead another in terms of how deep you go with the characters, or what world leader is rocking at any given time. I was excited to get into StarCraft because it is so much more linear, and it is about just a couple of people, and it is something goofy like a love story."
That love story is between hard-drinking space captain Jim Raynor and Sarah Kerrigan, a super-agent who ends up corrupted by the insectoid Zerg race. Trying to implement such a tale within what is essentially a war game is a different kind of challenge, which creates a different kind of friction - not between developer and players, but between writers and designers.
"To be honest with you, if I had a nickel for every time I heard, 'Really? You want to tell Gone With the Wind in the context of an RTS? Are you an idiot? That doesn't make it easy on us!'" he laughs. "And sometimes I wonder if we bit off maybe too much story for what you can actually build in the context of an RTS campaign."
So does story lead design, or does design lead story at Blizzard? "It's as collaborative as we can make it," he says. "Sometimes story and design are not always best friends - and I don't mean that in terms of our people and our teams, I just mean that purely thematically." But "we're not BioWare," he adds, and ultimately gameplay comes first.
"I think all things being equal, it's easier to manoeuvre story around design than it is the other way. At the end of the day, it's got to be fun and it's got to play, and it's got to be ideas that the design team can actually execute against. Whereas story, I believe inherently that there's ten ways to solve any problem with story. Or at least, of the two sciences, it's the one that's more adaptable."
Does it frustrate him sometimes, not having free creative rein in this "corporate art", as he calls it? "I guess I don't mind saying from a total, personal level that sure, that kind of thing to me personally is frustrating all the time. In my heart of hearts, I wonder did I just want to be a f**king comic book writer... So sure, I get frustrated all the time, not with the boys, but with the science.
"But sometimes I think it's in the clash of those sciences, and in the fact that we have to deal with each other and find that sweet spot in the middle without compromising the idea, that we have our moments of greatness. Through clashes of ideology, we stumble into moments that neither science would have conjured on their own.
"You're feeling the story, you're driving it, you're living it, you're tactilely interacting with it, and that's something that only games can provide. And I respect that. So if I ever get frustrated, I take a step back and I remember that we can achieve more than any classic narrative media can. And I'm honoured to be a part of it."