If you're not designing a discussion system, how is your design in any way relevant to designing discussion systems? It seems you're confusing a discussion with a debate. In a debate you have a lot of contestants, each voicing their opinion in a sort of sequential manner. In a discussion, you often see contestants pair off and start discussing the topic on their own, rejoining the larger discussion, or grouping with other contestants, after some time. Now, while a threaded, pure three-view, design of this might not be the optimal way, a sequential design is not really helping at all, as it is, as you say, forcing everyong to "discuss" with everyone. So... rewind... Are you confusing a discussion with a debate?