Written examinations as summative assessment; are they appropriate in PLT?

In ‘Why Study Emotion?’ in Paul Maharg and Caroline Maughan (eds), Affect and Legal Education, Emerging Legal Learning (Ashgate, 2011) 11 at 27-28, Caroline Maughan asks, ‘to what extent can the negative affect associated with formal assessment remain unacknowledged?’, ‘What is the real purpose of our formal assessment systems?’. ‘Should some of the time and effort devoted to coverage and summative assessment be traded off against using that time to offer opportunities for students to improve their understanding…’?. These questions are framed in the context of student motivation and satisfaction and their need for feedback (formative assessment).

I think they are important questions, and I add that written examinations often only measure a fairly limited spectrum of students’ cognitive processing (to see what I mean by ‘cognitive processing’, I have previously blogged about Marzano and Kendall’s taxonomy of education objectives here).
What are your views on written examinations as a form of summative assessment in PLT?