I agree with your first point that 'walled gardens' or closed systems like Lego provide consistency, however the second video in the linked article demonstrates

I agree with your first point that 'walled gardens' or closed systems like Lego provide consistency, however the second video in the linked article demonstrates a kid who I would argue is more creative by thinking beyond one system. ( https://vimeo.com/37778890 https://vimeo.com/37778890 ) In the video he is "thinking outside the box" and building a car by connecting three different construction kits. Of course this requires him to have an understanding of all three systems (rather than just one), but the potential is to build things by that would otherwise not be possible. [edit - link to video]