Bond markets? Don't get your hopes up. For the next 10 years, expectations are for returns in the 2- to 3.5-percent range; that's less than half of the 6 percent yearly average since 1926 and 5 percent yearly average since 2009. 

Volatility will be up, so savings — especially for retirement — need to be up too. Although the average savings rate for Vanguard-administered retirement plans is around 10 percent, including the employer match, McNabb said it needs to be between 12-15 percent, including employer match. 

2. Keep it simple — and cheap

Not only do investors need guidance in achieving their goals, said McNabb, but the path on the way to those goals needs to be clear. Simple funds, such as target-date funds, and simple services can steer investors toward a successful retirement. 

Oh, and by the way, that guidance needs to be low in cost, as do the expenses attached to investments. According to McNabb, costs for both must and will continue to drop. 

3. Build on the strengths of the system

While there are some criticisms of the U.S. retirement system, McNabb said that it should play to its strengths and build on them. 

He included defined contribution plans, such as 401(k)s, among those strengths, and suggested that automatic features such as auto enrollment and auto escalation of contributions must gain wider use. 

In addition, smaller companies not currently offering retirement plans for their employees must be wooed into offering such plans via lower-cost options. 

"Today, only 50 percent of people who work for companies with less than 100 employees have access to retirement plans (compared to 89 percent of people at large companies)," he said. "The cost and complexity of plans can be a challenge for small employers, but standardized plans that offer low-cost investment options can be an attractive alternative." 

4. Beware of over-regulation

According to McNabb, regulations such as those that govern the risk of losses for banks should not be applied to capital markets, since such regulations if applied to asset managers would increase costs and stifle growth — including the growth of investor returns. "We must ensure the safety of our banking system while maintaining sound and vibrant capital markets," he said.  

5. Corporate governance isn't just an issue for individual stockholders

Times have changed since 1980, said McNabb, when only 6 percent of investors owned mutual funds and those who put their money into the market did so via individual stocks and bonds.

Now, however, almost half of all households are mutual fund holders, so corporate governance issues that used to be important to individual stockholders have to become important to mutual fund companies so that they can represent the best interests of their shareholders.

Mutual fund companies should, going forward, be prepared not only for proxy voting but to get up close and personal with the boards of the companies in which they invest — engaging in an "ongoing dialogue" and setting "clear expectations for how they approach their common goal of creating long-term value for investors."

Of course, Vanguard, the world's largest mutual fund company, already does that.