Consumers represent the lifeblood of the U.S. economy, and that presents a problem, says Jim O'Neill, former chairman of Goldman Sachs Asset Management.

"When the U.S. consumer is starting to be more than 70 percent of GDP, as it's threatening to do again, the U.S. structural story is not as powerful as so many people seem to now believe it is," he told CNBC. "It was, but it's weakening."

The economy grew 2.4 percent last year, its strongest performance since 2010, and analysts expect an expansion of about 3 percent this year.

After the financial crisis, the country began to increase its savings rate and investment, with the importance of the consumer sector shrinking, O'Neill said.

But in the last year, it appears "the consumer is back to being king," he said. "In some ways, the reason we had the whole mess [financial crisis] in the first place is because the U.S. consumer was too much of the king."

Meanwhile, Glenn Hubbard, dean of Columbia University's Business School and former chairman of the Council of Economic Advisers under President George W Bush, sees problems with President Obama's economic policy.

The goal should be to "advance growth, work, and economic opportunity," he writes on the Financial Times web site.

"To do this we must go beyond the current triangle of trade-offs among jobs, income security, and near-term budget outcomes. This triangle is really a tri-lemma—in trying to achieve two elements, we miss the third."

That leads to inadequate policy, Hubbard says. "For example, a focus on employment and short-term cash savings led to temporary stimulus following the 2008 financial crisis, instead of the larger jolt to expectations that the troubled economy needed (and needs) for a real recovery."

In addition, Obamacare emphasizes "income security and near-term budget outcomes . . . at the expense of employment by taxing work and imposing job creation penalties on businesses," Hubbard says.

The solution? "We need a different triangle emphasizing growth and opportunity, making work pay, and long-term budget goals," he writes. That can include wage subsidies or an expansion of the Earned Income Tax Credit.

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