Many children don't relish the thought of writing. And I have seen that writing skills in general in the U.S. are diminishing. It's both a problem of literacy, and, I believe, a problem of lack of practice. Children simply aren't required to write as many essays and that sort of thing as they were when I was in school.
My own children have not liked to write, and I don't like to really force them to study anything - after all, education is only as good as one is willing to receive it! When was the last time you learned something against your will? How did that go?
Probably not great. You probably resented the instructor, and disliked the subject.
Instead of forcing a lot of essays, I encourage my children to write emails to friends, journal entries, song lyrics, short stories, poems, and reports on those things that really interest them. I have found the "Everything You Need to Know About English Homework" to be very helpful. I especially like the section in there on Roman Numeral outlines. I find it makes writing so much easier for the kids - they can organize their thoughts, then just get down to business.
Sometimes we create stories as a family, and we read lots of stories and poetry. This really sets the stage for writing, I believe.