Sometimes the right ratio of devices to kids is 1:25. And when done well, it can still be pretty transformational for the learning environment.
I really like the way in which you have framed the usage of a single device in the classroom. It isn’t about doing everything with it that you would do within a 1:1 environment, but rather it is about using it strategically and going further because of the constraint.
In particular, I LOVE the concept of Gorilla Blogging. The idea that students are capturing things from your classroom and sharing them to a single place. It reminds me of the “Scribe Posts” that a good number of math teachers were doing around 2006, but with a greater emphasis on students choosing what they want to write about. Just by giving a kid a device and telling them to capture their learning, you have empowered them to make something that wasn’t possible before. I would love to see blogs (or other types of social media) dedicated simply to students showing off the heavy thinking and great ideas from their own projects.