I was disheartened when I saw it as a cave instead of a guild
...I would like to see it return in an upcoming fable as its formal glory (or maybe have the ability to restore it in fable 3 ^_^)

That's a good point they could have taught others.Well it may be sacred the same way the Washington monument is to Americans. There have been hero's from other lands were they were trained in Albion also? I guess Thunder could be from another land but he and Whisper were the only black people i remember seeing in the original Fables and if there is as many Heros in other places as there are in Albion then it would only make sense that there would be other guilds.