With signatures, I found that messing about with the font size etc to make it look like a separate thing to the main body of the text helps, but then I noticed that nobody else had a sig so I binned it anyway
As for the other stuff - yes, the quote tags are rather pointless as you may as well just copy/paste for the exact same result... With the last set of alterations, everyone should have access to all the text-changing stuff as the Keymasters so while it's annoying to do so, it's possible to make quotes actually look like quotes.
On the Reply thing: clicking the "... minutes ago" bit next to the thread title will take you to the last posted comment whether it was a reply or just a new thing. Helpful in a thread that doesn't get a lot of replies but where someone's dived into the middle, pot luck if it's a busy one. And a nightmare in ones like the introductions thread where stuff appears all over the place because a comment that a bunch of people replied to got deleted...
All seems to be general wordpress stuff, so unless they upgrade so that more messageboard-friendly bells & whistles get added (unlikely), we're all stuck with it
