My understanding is that the elders are trained to only skim the letter and find the part where it is stated that they no longer want to be a JW.
That's why I never wrote a letter to the elders. I wrote one to my mom and dad instead. I think it made some points with my mom.
Later, when I gave my personal testimony at my church, I had it video taped. I mailed a DVD to mom and dad.
My dad wrote back that he took the dvd to the back yard and chopped it up with an ax.... true story. At least they can't accuse me of being "weak"; which is how most members who leave are described.
It was important to me to defeat the WT on their own terms, theologically.