"To Whom it May Concern -
I will not purchase an unrestored version of the original Star Wars trilogy. Release an original trilogy remastered to the best of current technological abilities and I will buy it immediately. Thank you."
They don't have armies of people going through mail. They have a few people who open and scan and if they don't see yes or no right away they don't bother. They're not interested in the heart-felt poetry of thousands of fans, just a bottom-line assesment so they can get a pulse on the public reaction. Yes or No is really all you need. Giving a brief reason why is good, as is a brief How to Turn my No into a Yes. Brief. Brief.
For a stronger letter you might want a "boycott" sentence in there: "I will not purchase an unrestored version of the original Star Wars trilogy, nor any version of the Special Editions - ever - until such original restorations are produced. Further, I will not support future Lucasfilm projects, promotions, or product offerings of any kind until this is done. Release an original trilogy remastered to the best of current technological abilities and I will buy it immediately. Thank you."
They don't care about you being nice. They care about money. You don't hurl insults or be an a-hole, you just state the facts and move on.
_Mike