#1: Concerns you know about and should do something about.

Of all the issues in this category, the most prominent deal with deferral rates (aka the employee's ability to save). Smarter employees recognize the need to save more. The trouble is they put up self-imposed obstacles that prevent them from saving in a timely way.

A lot of ink has been spilled on correcting poor savings habits. The most direct way to resolve lagging deferrals is through the plan document. This would involve our two favorite "autos"—auto-enrollment and auto-escalation. This takes the decision right out of the employees' hands and gets recalcitrant savers started on the path to retiring in comfort.

But these auto programs are usually not enough. Higher deferral rates are needed. For this, employers can restructure the matching algorithm by extending it to a higher percentage of one's salary.

This needn't increase the cost of the matching program, as the entire range can be shifted to higher percentages (e.g., a dollar for dollar match not on the first 3 percent but on the second 3 percent of an employee's salary).

Likewise, the range can be extended but the match dropped in proportion. For example, instead of a 100-percent  match on the first 3 percent, make it a 50-percent match on the first 6 percent.

#2: Concerns you know about and should do nothing about.

Most of the investment concerns fall into this category. Face it, (and this is a difficult reality for those in the investment business to admit), investments, beyond a certain, easily attainable threshold, simply shouldn't be an issue.

Employees need to focus almost on the things they can control – i.e., when they start to save, how much they save, and when they retire – and not on the things they cannot control – i.e., investments. The best way to "do nothing" about concerns like this is to reduce the likelihood of them sprouting up in the first place.

Once again, adopting a "21^st century" plan design can help. This means using a "tiered" or "category-based" investment option menu with heavy emphasis on Qualified Default Investment Alternatives.

#3: Concerns you don't know about and absolutely positively need to do something about right now.

This is the most dangerous group. It lurks in the shadows. It won't show itself until it is too late to do anything about.

These are the concerns you should have anticipated, and will be blamed for when they finally do surface. How do you anticipate these concerns when they show no warning signs? That's simple. Read.

Engage your peers (conventions and online communities are the best way to do this). The most important thing to know for #3 is this: Just keep swimming.

In other words, never lose your zest for learning, never accept the status quo, and never, ever, believe you know everything.

It's true, 401(k) plan sponsors have many duties, but they only have one worry. They worry their employees won't be satisfied, for whatever reason. If you can proactively appease employee concerns, you'll be a winner in the eyes of the plan sponsor.