Virtually all subjects expected the regular assignment of essays, not least of which were Charms and Transfiguration. Even Potions, if I recall correctly, required the ability to submit reports with accurate and reproducible procedures for brewing. You're correct that much of the first year, in my day, was spent assessing students' ability to follow logical progressions in their essays, as it was this skill that would enable them to do the theoretical work which would later be expected of them.

Properly speaking, History of Magic ought to have been the proving ground for essay-writing, but--well, when one is unable to dislodge the ghost from the classroom, it makes for a difficult standard.