Is your rater supposed to write your evaluation?

If you are not contributing to your eval you are not helping your own cause. That being said, your rater is "supposed" to do the eval.

Back in the day, I wrote most of my evaluations as well as a list of possible comments for the endorsers. Of course my rater had the ability to edit any or all of the comments and the endorsers were free to use my comments or write their own. Mostly they used my prepared comments, as I recall.

Fact, the system is broke and evals are consistently inflated based upon date of rank. It is a magical occurrence, but average officers become awesome every time they go into zone. There is a tremendous benefit to promoting being average as the vast majority of people are not exceptional. However, the system is broke and if you find yourself in a promotable status it doesn't matter how good of a job you do the next year, as most likely you will not get the highest block check.
Always write a draft of your eval as unfortunately some officers cannot write and in a decentralized environment the writing ability of your rating scheme means a lot more than your actual accomplishments. Take care of your Soldiers and just realize that a lot of your superiors benefited from a flawed talent system and now they are your boss.