First of all, your statement is invalid. That is because most of the people on this site are able to write a thousand words. Hell, I became Chunin by writing more than 1,500 words. Also, declarations were never meant to be easy. You have to have advanced literary prowess and some other qualifications in order to be moved up. Besides, people can use these essays to learn from their mistakes and become better writers.
I acknowledge that not everybody is a perfect writer, but moving up in rank was never meant to be a cakewalk. Or that's at least what Corren, Lucine, Crylancelo and Wabbitaro thought when they were making the Combat system and such. If you move up in rank, it shows that you have the qualifications of being Genin, Chunin, Jounin, and so on. It depends on how good a writer you are.
Personally, I don't think Declarations are hard at all. All you have to do is have the intelligence and prove that you are worthy of advancing to the next rank. That shouldn't be very hard to do, considering that most of us do essays in our schools.