I do think that writing letters to the Watchtower itself is futile. Those who are still faithful members will simply ignore your constructive criticism because that's what Jehovah's Witnesses do. They won't accept criticism unless it comes from the Governing Body. They have been conditioned to hold apostates in the highest contempt. Now, the Governing Body itself will ignore it as well because they don't give a shit. I used to accept, at the very least, the possibility that the Governing Body members genuinely believe what they preach. However, I've come to think now that they don't actually believe this stuff.
The lies, the manipulative tactics, the reluctance to change obviously harmful policies (such as forcing child sexual abuse victims to face their abusers): these are the things done by those who want to exploit naive, unsuspecting and innocent people. The Governing Body will not change their policies as a result of constructive criticism because they don't want to change. If they did care about change, they would've removed their policy to force abused kids to face their abusers long time ago of their own accord. It's the type of policy that everyone knows is extremely harmful. However, they changed that only because of the ARC. What that means is that to make change, you have to force them to change. Outside pressure is the only thing that works on them, unfortunately.