Reflection - Providing Structure - "too much" or "too little"?

This matter about "structure" seems to be coming up serendipitously. At the same time I've reconnected with Vance Steven and his education blog.
http://advanceducation.blogspot.com/2008/09/connectivism-too-much-noise.html
He had recently commented on an item by George Siemens on

"how structure influences the ability for students to learn. Too much noise and learners are overwhelmed. Too much order and learners are not challenged. Some ambiguity in the learning process permits room for exploration and creativity." Noting that the course itself was 'traditionally' structured, he said "it's the conversation that's more chaotic...does that detract from the learning experience?"

THAT caught my eye... and so I read on.

I would say, too little noise, too little challenge definitely, but also too little emulation of what the real world is like. In fact, ambiguity is rampant and managing work and learning tasks involves filtering and reduction. If the work of filtering is done for you then the opportunity to learn is reduced, not only of the knowledge to be acquired, but of the heuristics to be applied in the real world.

I interpreted his point to mean that relatively unstructured "learning" environments are potential opportunities for students to learn how to manage these moments just as they/ we will be expected to do in the real world. So as educators we're left with yet another important decision to make when designing learning - how much structure is appropriate to provide for students at a given time? The problem becomes even more difficult to resolve in the context of elearning where we may not know the strengths / powers of our learners to overcome "planned" ambiguity until they tell us or somehow indicate it to us.