In addition to the Ferry Riders Opinion Surveys (F.R.O.G.) you can also provide input on a variety of transportation issues to the Washington State Transportation Commission (WSTC), the governor, state legislators, and other decision makers by participating in the Voice of Washington Survey (V.O.W.S) group. The current survey for this group is directly addressing the ferries, so you may want to join and add your two cents.
The current F.R.O.G. survey is also still open. If you have not already responded, you still have time.