>>13 No, Random doesn't have "implicit rules regarding the type of content" they can make a thread about. It's just the same general rules that apply to every board on the site and just about every active forum in creation. If you make a thread in Art with just one drawing and "cool" written, it would get saged when a mod saw it. Sure, it fits into art, but it's not a proper post that anyone can work with.
If you honestly think we need to explain in the FAQ the basic concept of a thread, then add that to it.
"Which, by all accounts, is quite random, but most if not all of those would get permasaged if someone made them now."
1) Arch's wouldn't be saged. There's a point to the thread that encourages more than a few posts of participation without duplication. I might recommend we do a fuzzy math thread in general instead, but it wouldn't be a big deal.
2&3) Would only be saged because it'd be a duplicate of the con thread in Countries.
4&5) Would have been saged then and now.
But most importantly, remember that the mods are only human and miss(ed) a lot of threads throughout the site as they slip into the archives even nowadays. Just because it's around in the archives doesn't mean it's supposed to be there. All you're doing is proving just how fast threads sink and how easily they're missed, pushing my reasoning for why a free-for-all board wouldn't work.