Writing a letter - reasonably worded & clearly outlining the situation would be the best way to proceed. A screed slamming & damning stuff goes into File 13 and is not taken seriously by anyone - not just HD.
The time frame for this proposed letter is not so good - the MoCo has only recently announced what they plan to do & it applies to all the 110's produced prior to April 08. Any response to such a letter now would elicit a response from the MoCo that these problems are being addressed by the current "fix". No failures from this new "fix" have been reported, again due to the time frame we are currently in.
People that are upset about the details of the proposed fix are certainly within their rights to complain, but doubt it would get anywhere currently. In the past these complaints are what generated the response from the MoCo, however.