Opening different threads for subs and raws, sounds quite pointless as well. Similar threads just because some people are about a week ahead. (and there are also people who can watch both raws and subs~)
And, even if you do this, it still doesn't mean that all the spoiling would stop. There are still those who have read the manga, and can spoil the fun even for those who watch raw-animes. And there are still those, who are far behind with the anime and manga, and can consider pretty much anything as a spoiler.
So i think that there should just be a rule about spoiling, and then give bad rep/warnings/ something else if they give any major spoilers.

And can't the thread-starters just add in the first post, that IF the spoiling is allowed, it has to be done with spoiler-tags. And then give a short list of what is considered as spoiling? that wouldn't take too long, and would make things easier~?