Btw, thanks for bringing this up, the Dead Pile was made visible as an experiment, but I think it's long time it was hidden again. We already raised the issue with the Admins.
Back on topic:
1. Keeps debates contained in one place for easy reference. Allows a stickied thread with a list of dos and don'ts.
You can bookmark your favorite debates just as easily. We already have that, with no need of a child board for having it.
2. Keeps things organized, possible debate clubs.
You can also do that yourself by not allowing the "bumped" topics to say on top every time. Clubs are just... a bad idea, from our personal prior experience, believe me. Also, "clubs" will form anyway in every debate, since people will side with whoever believe what they do. And it's easier this way, since we might agree on one subject but not on another, and belonging to the same club would end up being awkward.
3. I'd also ask that a user could be able to 'turn off' the child board in his/her profile if that person so wished.
We also happen to be able to not access those threads, but a lot of users end up doing it anyway, it wouldn't solve the issue.
4. People wouldn't have to post there, if someone didn't like what was going on they could wait until either people had exhausted themselves or the mods had stepped in after it turned into one-line insults and/or graphic pictures.
The idea is not having to get down to this point.
I understand that you'd want to advocate having a child board for your favorite types of "open content" topics, but then, so would everyone else, and it's not fair to do that to only some users, and it's not easy to go splitting the CoC in about 6-7 boards, because things would get REALLY confusing as to wether some topics would have to go, and you guys would end up having us mods running around like ants moving stuff back and forth, ASIDE from moderating. It's just not worth the trouble, for very little gain.