Part of creating engaging assessments involves offering students choice in means of expression and, as Mike suggested, there may be room to express and explore ideas through writing as well as video, visual art, dance, music, etc., each with their advantages and pitfalls. It has helped that I have, perhaps more than some other English teachers, a background in visual art, music, and theatre that allows me to create fair rubrics and provide instruction in how to meet quality indicators that are more specific to these media. I know some teachers focus more on speech and writing because that is what they feel most comfortable fairly assessing. In my experience, though, even when I allow students the option to develop and share their ideas in a format that does not involve writing, I've felt more confident in my ability to fairly assess their thinking if I have them explain what their intentions and ideas were in some form of supplemental writing or an oral interview - the stuff of essays, articles, blogs, and vlogs.
While I think the audio-visual format is more engaging and accessible than plowing through pages of writing, part of my reluctance in having students create videos or vlogs has been the fact that I know it takes the first step of creating a quality script in writing and then substantial time filming and editing - time that would be well-spent but needs to be balanced with the time constraints of the class and the demands of the curriculum. But perhaps this is also a result of my own inexperience with filming and editing.
Part of becoming a more effective teacher and communicator involves enhancing my skill sets. Mike and Idea Channel have provided wonderful inspiration for me not only to have and develop ideas, but to try doing so through a variety of media, and to bring my students along in this journey.