What kinds of criticisms do you think should be included in the letters?
It would be more effective to write to ISU headquarters or to members of the ISU technical committees than than to write to random tech specialists or judges who happen to live close to you -- they're just applying the rules, not necessarily at the events you're criticizing. You want to address the folks who make the rules.
Of course, if you actually get to meet a local judge or tech specialist and have a conversation about skating, by all means express your thoughts. They might agree with you on many points. They might have a good idea of where to address those observations.
I don't think it would do much good to criticize specific calls at specific events that resulted in unpopular results. The tech panels were just calling the event as well as they could in real time. Maybe they made a few mistakes, but it's too late to do anything about it after the medals have been awarded.
More comprehensive, thoughtful critiques of some of the rules, directed at the people who have the power to effect changes in the rules, might have some value.
E.g., maybe argue that scoring triple jumps just over 90 degrees short as if they were double jumps is too harsh a penalty compared to the difficulty of peforming an almost-rotated triple vs. a double, and it's confusing to audiences who see apparently successful triples. If enough fans and skaters and coaches and even judges express that opinion, maybe they'll choose a more generous point at which to draw the downgrade penalty and a less severe way to penalize moderately cheated jumps.
Or complain that too many of the step sequences, spiral sequences, and long program layouts look like they're following a template and limiting skaters' ability to showcase their individual strengths. Lament the loss of quick footwork that flies across the ice and spirals that interpret the music, and ask whether rules could be rewritten to encourage skaters to show off those skills.
Maybe if the decision makers hear enough voices asking reasonably for the same kinds of reasonable changes, they will consider making those changes.
That's exactly where I was going with this. I think talking to local judges/technical specialists can help garner support for them to go to the people who do make the decisions and/or help direct criticism to the proper people.
I think that it's super easy to go-off on a message board and rant, but it's much harder to actually take the time to find out how to take those criticisms to the decision makers. It takes time.
And perhaps people on this board could work together to write a letter, or maybe start some sort of effort to get the conversations going across the country. I think writings by people like Phil Hersch brings the issue to light, but it's up to those who have a true stake in the sport (whether as a fan, skater or coach) to find ways to keep the conversations going.
And in those conversations they can not revolve around one competition or skater. Doing so would actually reduce such criticisms as ones being made because a favorite skater did not do well.