By removing the ability to respond to specific posts, you're almost forced to provide a thoughtful and coherent response to fit into the natural progression of the topic. This could eliminate flames, cripple fights, and identical responses. If each user would read the entire thread, they could then decide if their post adds any value or fits into the flow of discussion.
This could bring about a positive change to the overall content of the board.
Of course, while I'm wanting for the virtually impossible, I'd really like to win the lottery.