Limerick may have a point. Teaching, like any profession, thrives on the pompous language that puts distance between expert and novice, but I doubt we take revenge on our students by purposely remaining aloof. Many of us would welcome any opinion, dissenting or not. We encourage critical thinking in essays and term paper assignments, but there are limits to what students will say when a grade is at stake. I see the value of both.
Expressive writing is less structured.
There are trade-offs, of course. Time spent minute writing means fewer hours devoted to content. It means relinquishing some control in the classroom and frustration, perhaps, if the effort is not rewarded by productive interaction and talk. But consider the alternative. We also miss a chance to legitimize student concerns.