>>3 It may be so that News has more threads than Main, but in either case, there aren't enough related threads to be categorized.
>>1 We do not get enough posts in specific places in News for there to be sub-boards for every country. The most recent News stories are always the top 50 (plus some old ones that get bumped up). They're not hard to browse through. Those are the only things people really need to look at; there's no reason to categorize old news for people to browse through, because it's not news anymore. If you're really curious about old news, you'd probably browse through them by title anyway, regardless of where they happened.
Of course, those are my personal opinions and assumptions.