This is a cool idea. I'm not convinced that having all the comments in a sidebar with size constraints is going to be that useful, though. It might work better

This is a cool idea. I'm not convinced that having all the comments in a sidebar with size constraints is going to be that useful, though. It might work better with traditional chained comments but having the radial diagram floating to one side. Also it's easy to imagine posts starting out too small to click on and getting lost in the noise. (Not that this doesn't happen in other formats.)