Let me try to address them one at a time. The better able we are to stand back from our subject matter, to hold it at arm's length, so to speak, the better able we are to produce such discourse. I think the product mode versus process mode is a misleading and false dichotomy.
All discourse forms are products of language use, of distinctive language and thought processes.
The important point here is that product versus process are pedagogical emphases, not inherent characteristics of particular discourse forms. I'm painting these contrasts pretty broadly for effect, but fairly accurately, nonetheless, I think. For instance, both expressivists and social constructionists regularly use and highly value peer editing and writing workshops, but do so for very different reasons. Every writing textbook I have ever seen begins with personal writing and then moves toward more academic topics and forms. We need to move in close, then move away, then move in close again, then move away again.