Rethinking Minimum Word Requirements

Anyone who's ever had to write an essay with a minimum word requirement understands the frustration of having to fill up pages with BS. I can understand why a lot of teachers impose these limits, but I don't think they have the effect we desire.

Desired Effect:
Students are thorough enough to complete the assignment.

Problem:
The assumption we are making is that there is a specific, optimal range of words for discussing a topic and that we know what that range is. Unfortunately, as we've all witnessed as students, teachers are often wrong about this.

Actual Result:
Students learn how to write using more words. They learn how to sound intelligent while filling up many pages to say very little. They become overly wordy, ineffective written communicators. I didn't fully realize this until I started blogging. In preparation, I began reading up on tutorials for what makes good blog writing. Everywhere I looked, I saw one thing in particular: don't be overly wordy. While writing, I keep finding myself breaking this rule and struggling to slim down my posts. Strangely enough, my writing was always considered very good throughout high school and university! Now I'm realizing I have a lot to learn (and unlearn) to be a more effective written communicator.

Alternative:
So instead of imposing minimum word requirements, how about just being very explicit on what we want students to include and giving them suggestions for about how long we expect the essay to probably be? I think that flexibility is more realistic, gives the students who need it a measuring post, and with at least one rough draft, we can ensure with feedback that students are in fact clear about our expectations.

Could this work a lot better or am I missing some crucial element that justifies the use of minimum word requirements? Let me know what you think in the comments...