Very thought provoking. In Intro to Soc classes in the US most teachers tend to rely almost completely on multiple choice tests. As a GA in a Soc program I admit to succumbing to this easy way out, mainly cause everyone else was doing it. But I never thought it was a good measure of what I was really trying to teach. What I wanted more than anything was for my students to lean to use the sociological imagination, to learn to think critically on a societal level as opposed to meeting societal problems with individual solutions. I think this could better be done with essay tests, which I have always preferred as a better assessment of knowledge (but for reasons you address, they are certainly not perfect either). But they are not only far more difficult and time consuming to grade, but with a subject like sociology you are bound to get complaints from students who feel you are marking them down simply because you do not agree with them politically.
RE: Seven reasons why written exams are an invalid measure of students' ability