If I have it right, in the Ed Tech Weekly #204 session you suggested that success is learning to learn rhizomatically, the above post perhaps elaborates a bit further on that point.
If I’m interpreting you correctly from the and what you’ve written above, the traces of the rhizome offer a picture of the learner’s journey and efforts (reflections, summaries of learning, etc.).
I think you’re just saying that because you have to assess learners due to institutional requirements you’d have to view it as a review of an individual learning experience. So I don’t think you’ve gone far off from your earlier thought. Or maybe I’m off-base!

Something I’ve been thinking about: I am starting to see learning in MOOCs as an exercise in building democracy. It’s messy but it helps build capacity, as Alec once said to me. That translates to (21st Century) literacy. If we can develop this literacy en masse, the possibilities could be amazing.