In Slate, Heather Chaplin does a good job of pointing out why this is generally a lame idea.
What she misses is that there are legitimate reasons why people feel they're achieving less. These include the boring literal truths of jobs shipped overseas, stagnant wages, and a taxation system that benefits the rich and hurts the middle class and poor. You want to transform peoples' lives into games so they feel as if they're doing something worthwhile? Why not just shoot them up with drugs so they don't notice how miserable they are? You could argue that peasants in the Middle Ages were happy imagining that the more their lives sucked here on earth the faster they'd make it into heaven. I think they'd have been better off with enough to eat and some health care.
I think McGonigal wants to try to harness the powerful, short, positive feedback loops provided by games to make work seem less like work, but this idea ultimately has two big problems: it feels like we're being scammed, and it might just suck the fun out of all games.
On the first point, adding achievements, power-ups, and persona to school, work, and chores seems akin to pouring chocolate on lima beans. In her book, McGonigal gives examples of people who compete with each other to try to clean their own bathroom, because it's worth so many points in a virtual game. I don't buy it. This might work for the near term, but scrubbing the toilet sucks. I don't think thinking "Wow, this is going to level up my in-game rogue" while I scrub the toilet is going to make it that much more fun, especially in the long-term.
And to the second point, I think correlating game-like experiences with hum-drum tasks may take the sheen off of other games you play. Games are one escape from the necessary tedium of life. As McGonigal points out, they are highly-simplified abstractions of the more complex, messy aspects of the world. In a game, we generally have very clearly-defined goals, with a limited range of choices. And when those choices pay off, we get artificial rewards that stimulate the parts of our brains that are hardwired to respond to real-world rewards.
The move to try to meld the escapist simplicity of our video, board, and card games to the complex tedium of the real world is well-intentioned, but as Chaplin points out, horribly flawed.