No. At least, it hasn’t proved to be so in practice. I don’t know where you get “several simultaneous threads all on the same subject” from anyway. There is the formal debate thread, and then there is (possibly, but not necessarily) a thread where people are discussing the debate. That’s two, not several. One is an actual debate, and the other is what we currently have.
With respect to a poster taking a break because he feels overwhelmed, that’s a fine solution if a thread is indeed a pile-on. But what this idea tries to achieve is elimination of the pile-on to start with. If a thread comes to the point where someone feels overwhelmed and tensions rise, that’s not a debate — it’s a struggle to see who can make the most noise. It might be a Great Topic, or a Great Free-For-All, but it isn’t a very Great Debate.