She'll have help from Mark Reuss, who took her job as the head of global product development. The two have the chops and vision to force GM designers to stay focused, but now they have to show it.
Will every model they roll out be a hit? No.
Will there be a clunker or two in there? Probably.
They won't bat a thousand, but if they have more hits than strikeouts, it would go a long way in keeping GM competitive.
Push middle management and old guard
The other challenge Barra faces is pushing GM's middle management and old guard to think and act differently—something that's easier said than done.
She saw the absurdity of some long-entrenched GM rules and habits when she was in charge of human resources, which included an out-of-touch, 10-page dress code. Talk with enough executives in middle management at GM and you'll hear similar stories from other departments: many have been there for years, and they realize some of the practices are cumbersome and should be revamped.
(Read more: Government sells the last of its GM stake: Treasury)
Can a woman who grew up in that culture force it to change? Her track record says yes. But another problem plaguing GM is that the farther up its executives climb, they become less effective in getting those in middle management to move faster.
One example is Fritz Henderson, an internal selection who said that he would change the culture at GM when he took over for Rick Wagoner in 2009. He was only around for eight months and failed to make major changes in how GM operated.
If Barra can buck that trend, she has a shot at being a transformational CEO—and not simply because she's the first woman to run General Motors.
—By CNBC's Phil LeBeau. Follow him on Twitter
Questions? Comments? BehindTheWheel@cnbc.com.