I have seen some discussion of why USMS isn't attracting the typical fitness swimmer. Here are a few suggestions from an old slow poke newbie.
1) Motivational times. This may be of interest to many on this forum, but to someone starting out with no race experience, they can be highly de-motivational because they all look unattainable. If one cannot even approach these times, one may feel he does not belong in USMS. Why not extend the chart all the way to double the time in the first column? Say 10 columns from 10-100% slower.
2) One Hour Swim. An hour is a long time for the casual or new swimmer. In running, a marathon is too long for a newbie, but almost anyone can train for a 5K, 10K, even half-marathon within a short time running regularly. Why not have a half hour and 15 minute swim too?
3) Embrace Triathletes. In summer I swim with a Tri club at a local lake. There are often upwards of 100 people there doing 1, 2, or 3 laps on a half mile loop. And they are not slow. I swam a 1 mile USMS event in Lake Placid, NY last August with far fewer than 100. Why not partner with Tri clubs for some events, pool in winter, open water in summer?