One week to go - help me form the keynote

In a week I'll be in Sandvika, working with teachers, in-house, on developing design thinking skills as a way to approach curriculum, content and formative assessment. The keynote, the following day, has the title of "Opportunities around the world in building effective learning communities". It's large in many senses, and I want your help to shape what we talk about:

1. What are your biggest challenges in collaboration, in your own classroom or with schools overseas?
2. Does collaboration always add value to learning? Is it an overused word? An overused strategy?
3. How do you work out if you want students to collaborate or not on their learning? Is it a decision you take? Or is it one solely in the hands of the learner?

Please do take a few minutes out of your day to reply to this, however quickly, so that I can try to get the angle of my talk just right for you. Many thanks in advance!